1) Hinduism is diverse, with dozens, if not hundreds of sects, cult centres, philosophical schools, and so on, and yet all are Hindu, in their own way. Until about sixy years ago, at the very least, “Hinduism” was more often described as “Hinduisms”, as a plural, because ultimately, the only thing uniting most Hindus is a shared pantheon of deities and, to a lesser extent, some shared narrative mythology. Most sects have a minimum base of shared practises (but I’m only saying “most” based on my knowledge, which is naturally more limited than someone who not only practises it, but is well-informed on the practises of all other sects.) Some sects and schools are as different from each other as the Christian sects (with the Catholic opulence and the plain clothed Quakers and Jehovah’s Witnesses who abstain even the most basic celebrations as “pagan” in nature).
In evolutionary biology, species that are described as “generalists” are at a statistically higher rate of survival than species described as “specialists”. Religions work in kind of the same way: While the Nicean council and crusades were somewhat successful, for a relatively brief period, in wiping out all dissenters and heretics, this was doomed to ultimately fail. Human beings are kind of an “ultimate generalist”, as a species; there is very little we won’t eat (all things considered), and somewhat less that we simply cannot eat (though as more studies of industrialised food happen, it seems that list is slowly growing), we’ve found a way to survive in all manner of environment, even in pre-industrial cultures, and we may be closer than ever before to being able to terraform places like the Moon and the planet Mars. Humans, by default, crave diversity, and this includes religion; there will never be a “one-size-fits all” religion, which is exactly why Dominionist sects of Christianity are not only politically dangerous, but also, ultimately, doomed to failure as long as we can keep those in those sects out of power.
While there are certainly definable elements in Hinduism, that family of religious practises and philosophical schools is impeccably diverse within those defining elements, more so than most other religious groupings1, and this is certainly one of the ways in which it endures. What Celtic. Germanic, Roman, Hellenic, and other polytheist reconstructions can take from this fact of Hinduism, is that the former “Hinduisms” is more accurate. When we look to ancient polytheisms that have sufficient surviving records of their practises by the people who practised them, we see this diversity mirrored –there were dozens of competing philosophical schools in Hellas, Rome had all manner of fringe cults to even her own gods, and the Egyptians had a degree of diversity in religion, as well. Considering that the Germanic and Celtic tribes were more loosely organised than even the Hellenic tribes (even though, contrary to popular Romantic misconceptions, there were even cities founded by the Celtoi and Norse), it makes sense that there would be just as much diversity as what the Hellenes had, if not moreso. To therefore preach a “one true [tribal] polytheism” is to display a fundamental misunderstanding of how polytheism naturally works and evolves, especially as there is a living example of this in Hinduism. This said, is anything or everything Hinduism? Of course not, there are still definitions of what is and is not Hinduism, what is and is not devout practise within that broad definition, and so on; the point is that the definition is broad, not narrow.
2) Many Hindus can get along just fine, in spite of theological differences, because it’s not about belief, it’s about practise. Yeah, some pagans like to gloss over some of the less savory parts of Hindu history that make it clear that different sects haven’t always peacefully co-existed, and I’ve seen some commenters on TWH seem completely ignorant of the bloody history between Hindus and Muslims on the subcontinent (and then some other people completely ignore the fact that, much of what Hinduism looks like today is a direct result of British colonialism, and thus they blame Hinduism itself on some of the injustices in modern India, rather than British colonialism and its Christian influence —but that’s another story for another time), but many Hindus are still perfectly willing to put aside *some* differences, as long as all parties involved are still otherwise compatible in worship.
When looking to surviving texts on ancient Mediterranean religions, we see some of this mirrored —it is not a faux-pas for, say, a Makedonian to enter a Eleusinian temple as long as the former takes care to observe proper etiquette, especially for Eleusis’ famous mysteries —similarly, I’ve known Shiavite converts to go to Hare Krishna temples because in that religious culture, it’s OK, unlike how in Christianity, it’s expected that Catholics will go to Catholic churches and only Catholic churches, and Methodists will only attend Methodist churches, and so on, and many sects and individual churches are still apprehensive about performing weddings between two Christians of different sect —I recall even, once, an episode of Cheers where a minor character had a bit of a crisis because she and her fiancee were two different variants of Lutheran. This is largely because Christianity is a religion of beliefs whereas traditional polytheisms are religions of practises. All you need to be Christian is belief that Jesus was “the only begotten son” of the God of Abraham, and hold at least much of the second half of The Holy Bible as a sacred mythos. There are some rituals in Christianity, sure, but the more “modern” the sect of Christianity is, the less important those are, and sometimes they’re even discouraged —many Quaker divisions barely have an organised clergy, and Jehovah’s Witness Kingdom Halls characteristically lack any sort of religious iconography— because what ultimately defines Christianity and its sects is what one believes.
What defines polytheism by the dictionary is belief, sure, but in traditional polytheism, belief alone is not religion —in traditional polytheism, there have rarely (if ever) been even words for “religion” in the ancient mindset, because religion itself is indistinguishable from “a way of life”. In Hinduism, you can believe in multiple deities with Hindu names all you like, but if you want to be part of that religious community, that simply isn’t enough. There is no real central authority, true, but there is an established culture of practises, even for converts, that makes you a Hindu, not just your beliefs. Likewise, the Hellenic, Heathen, Celtic, Roman, Canaanite, Kemetic, etc…, polytheist communities should accept as a given that people in those communities are going to believe in the Deities of those cultures, and even if certain individuals can justify a more pan- or panentheistic interpretation of their own personal belief in the gods, that’s ultimately less important than what one does, and how that belief is reflected in how one lives one’s life. From things as basic (and near-universal) as food offerings (even if it’s literally just a tablespoon of Frankenberry, or a fraction of a teaspoon of water, because you are just that impoverished) to stuff as complex and specialised as how one approaches medical care (I would somehow find a way raise the money to move across the world if there was a Hellenic equivalent of Ayurvedic medicine that came back into practise), these are ways that can, indeed, measure the degree of one’s devotion beyond merely believing.
3: There are formalities and expectations for converts before they can be taken seriously as a Hindu. I know a lot of people, Americans, especially, really wince at the idea of formalised religion –especially when American Eclectic Paganism is often very true to stereotype of caring more about what the individual wants to make time for than being a part of something bigger than the individual.
Now, formalised rituals are probably best left to groups that are essentially forming sects, but the notion that anyone coming to these revived religions ought to actually do things and not just believe in gods, that they should make some tangible lifestyle changes and not just re-frame their everyday activities as “an act of devotion” are not ideas that should be shied away from. While these religions are generally not truly unbroken traditions (at least considering the evidence, regardless of what a scant few people may insist on without evidence), unlike Hinduism, that doesn’t mean that an expectation for co-religionists to have a baseline of shared practises is somehow unreasonable. If Catholics and Hindus, Shintos and Santeria practitioners, each have a baseline of shared practise in each religion, it’s not unreasonable for a Hellenist to go to another Hellenist’s house and observe some not-insignificant degree of shared practises. Or Kemetics, or Heathens, or Gaels, or Gauls, and so on.
Are there less-than-devout Hindus who don’t carefully observe every practise in the same way that there are Catholics who’ve never had a household shrine and barely make it to mass outside of Christmas and Easter services? Well, it seems logical, so I imagine so, but at the same time, these are people who would hardly consider themselves to be “devout”, because that implies doing something more than they do. It may seem unfair, but converts to Hinduism (or even Catholicism) are generally expected to at least a little more devout than average –otherwise, what are you doing here, as they say. So when a religion is largely (almosg entirely) composed of converts, it doesn’t look right when someone claims to be “devout”, but in practice shows greater devotion to Doctor Who than to their gods, to say the very least. Hindus likely wouldn’t take such people seriously, so why should revived/reconstructed polytheisms?
1: For the purposes of this piece, a “religious grouping” necessarily shares a pantheon and some overlap of narrative mythology. Therefor, “Abrahamic” is a religious grouping that includes three different religious groupings, in and of themselves, but “pagan” is not a proper religious grouping, but a sort of socio-political umbrella under which many religious groupings have room.