Mrs. Don-o — while you are correct about tribal and caste matters playing a role, it may not be true in Kerala — Kerala is about 30% Christian (mostly the ancient MarThoma church — the Church of the Apostle Thomas — or derivatives). In the south a lot of the issues have been because, allegedly, pastors print materials calling hindu gods and goddesses as demons.
Interesting set of alternatives:
We've seen examples of the latter before: e.g., Santaria, the cult of Santa Muerte...and it's not too pretty.
But there is also a component of Indian nationalism that is involved as well. Particularly the Bhjaratiy Janata Party (BJP) and the more extreme Vishva Hindu Parishad (VHP). They both see Christianity as a remnant of European dominance. In fact, the VHP has a program of attempting reconversion of Christians (and, to a degree, Muslims). In some cases those attempts at reconversion are not exactly voluntary.
I'm not saying that this is anywhere near as bad as Muslims' actions in regard to the sanctioned idea of dhimmitude. But it exists.
There are so many variations of Hinduism, some of them arguably demonic (those that hate Christ and hate their low-caste neighbor are surely demonic!), and some leaning more toward ethical deism or toward Buddhism (non-theistic), with the various deities representing philosophical ideas or even folk heroes (equivalent of Paul Bunyan.)
I could not say it is all demonic.
I'm influenced by some pro-life Hindus I met when I stumbled upon a street fair in Oakland, CA celebrating community "involvement". I had on a pro-life T-shirt and decided to try my luck handing out leaflets.
I was soon approached by some very menacing people, mostly black and white, who gave off vibes of imminent harm. Then a couple of Indian women intervened --- they were running a booth touting vegan food and whatever god(dess) they were devoted to --- who yelled at the abortion enthusiasts and made them back off.
These ladies then patted my hands, gave me some dabs of hearty food to eat, and showed me pictures which indicated they thought abortion was "veddy bad, veddy bad." They didn't believe in killing anything.
This probably contributes to my friendly bias in their favor.
Some of Hinduism is a falling-short due to honest ignorance, some of it replete with natural virtue and without a vicious element. (I mean, every human culture has a vicious element, but the POST-Christian cultures are probably the worst.)
Everyone, without exception, needs Christ the only Savior; but some may have devoted themselves to Him as Way or Truth or Life --- as the Light that enlightens every man who comes into the world--- without knowing, even, that this is Christ.
As Paul said, these people "might seek God, and even perhaps grope for Him and find Him, though indeed His is not far from any one of us." (Acts 1:27)