In this question I generalized the concept that Steppe pastoralists immigrated to India displacing the agriculturalists who were at the time living in the Punjab region. These farmers then migrated south and east displacing hunter-gatherers who were living there. Linguistics has been claiming as much for decades and now genetics confirms the concept (see The Genomic Formation of South and Central Asia by Narasimhan, et al).

My answer was downvoted to the point it can no longer be seen. I found this curious, but didn't think too much of it until this evening. I was reading through the comments of a YouTube video and again saw an Hindu man claiming that this migration theory has been proven wrong. None of these people will provide counter evidence, but just says it is wrong—end of discussion.

So, why is it that Hindu's—despite well verified scientific research—don't agree that people migrated into their country?

Is this akin to fundamental Christians in America believing the Universe is only 6,000 years old despite all evidence to the contrary (in that they believe the histories presented in their sacred texts are literally true)?

Note: I will be impressed if this question gets an answer, but I expect as before the topic will be buried via downvotes.

Note 2: I have only seen this behavior by Hindus and not by non-Hindu Indians.

Note 3: I never claimed all Hindus do this. My experience is that only Hindus do this. So, what is it about Hindus or Hinduism in particular that makes this idea seem skeptical?