The whole "Republican Party becoming the party of white Christian bigots" is probably the biggest factor.
But on top of that you've got to realize that Indians who manage to immigrate to the United States are generally the cream of the crop from India. India is an extremely poor country, and so only the most educated and financially successful people are capable of coming here. You can't just walk across the border; you have to fly across an ocean to get here. Being educated and successfully getting a job here (HB1s and what not) usually require a British educational background with strong English skills, cultural awareness to assimilate, and the skills necessary for getting a job here (as already mentioned, doctors, engineers, business professionals, etc.). Generally, if you have such an education, you would find the culture that the Republican Party panders to (usually provincial, whites in the south and Midwest) to be a major turn-off, no matter how "pro-business" the Republicans are.
And even despite the "pro-business" image of the Republican Party, in India, the relations between business and government are radically different from what we have here in the U.S. India's first PM, Nehru, was an avowed socialist, and India's balancing act in the non-aligned movement lead to the formation of many socialist and communist parties who enjoyed great electoral success (again, remember that India is an extremely poor country), and the political narrative from 1947 to 1991 was that of Gandhian socialism. Though socialism in India was fairly unique to India, it nontheless has had enormous influence on the political views of Indians (including those who move abroad). Hell, I can go downstairs right now and pick up a pamphlet my mom had to read in school written by Josef Stalin (something about dialectual materialism, whatever that is). What Indians learn about the theories of socialism, communism, and capitalism are not discussed in the same way that they are here, where socialism and communism are automatically regarded as "evil". And since the United States increasingly sided with Pakistan and China against India in the 1970s and 1980s, India came to distrust the U.S. and trusted the USSR instead, which was pretty generous in helping India out.
So your whole "taxes are evil!!!" and "government is socialism!!!" thing, Indians don't really get in the same way that Americans do. If you come from a country
where people literally die in front of you for lack of a social safety net, you're not going to be very sympathetic towards the party of "less taxes, less social services"
And regarding business again, seeing the massive pollution and abuse of workers that is done by businesses in a poorly-regulated economy like India's, maybe Indian-Americans are pretty happy to have clean neighborhoods, air, and water.
Hindus are very family orientated and believe in strong family values which Democrats do not
This is true and all, but Asians in the United States are still committed to political secularism, even if they personally are traditional.
Oh yeah, and your point about Muslims is just stupid, considering the enormous influence Islam has had in India (and still does). I mean, we wouldn't have the f-ing
Taj Mahal without them. Yes, India has a complicated dynamic regarding Islam and Hinduism, but saying that Indian-Americans will vote against Democrats because they "pander to terrorists" or whatever is just really f-ing stupid. Did you forget that something like 15% of India is Muslim? Did you forget that a good number of Indian-Americans are Muslim? Or lemme guess, Muslims aren't "really" Indian.
What if I told you, that before 9/11, Muslim Americans gave 70% of their votes to George W. Bush in 2000? After 9/11, the GOP fully embraced Islamophobia and general suspician of "brown" people, so why the hell will Indian Americans voted Republican if Hinduism is targeted by evangelical Christians as a "idolatrous, cow-worshipping, pagan" religion? Why will they vote Republican if the Republican voter base views anyone who is "brown" as either a welfare, illegal immigrant leach (if you look Hispanic) or a terrorist (if you look more Middle-Eastern)?
