I'm not Indian so can't speak to that experience but discrimination masquerading as "culture fit" is just as rampant in Silicon Valley as it is in the rest of the US. This includes racism, ageism, misogyny and classism. If you don't think MIT/Stanford grads in their mid 20s at Big Tech companies have more doors open to them you're crazy.
There is a tendency in the West to view all minorities as somehow being the same. Like all Africans are somehow viewed the same in many ways despite their being significant cultural, religious and language differences that go back centuries. The same is true in Asia (eg a lot of Chinese in Malaysia face significant discrimination such that they end up going to university overseas because they can't locally).
So a deeply ingrained caste system like India's I can totally believe doesn't magically disappear because those raised in that system now happen to live and work in the United States.