The caste system isn't a part of the Hindu religion. It is a cultural issue.
If the caste system isn't part of the Hindu religion, then how does a slave of the culture escape such oppression...without having to be an illegal alien?
The caste system was inextricable from Indian religion in earlier days. The castes were connected with the divine order of things and with reincarnation. The Brits managed to cut back on some of the established customs, like suttee. And Ghandi's movement led to freeing the Untouchables.
But the strict, fanatical Hindus who go around murdering Christians and burning churches would pretty certainly like to restore the caste system if they had the power to do so. And probably burn widows, too. The question is, do they have the power to turn back the clock on things like that? Hopefully not. The leaders of Hindu nationalism are pretty ruthless, but they just don't have the kind of following any more that the Muslim leaders have.
Well, if it's a cultural issue (as you claim), how do you explain that their society--stratified by cast--fairly well mimics the Hindu relgion (Eastern Pantheistic Monism) in which life (Atman/Brahman) is reincarnated--get this--8.4M times before reaching Braham?
Stratifed social structure...stratified reincarnative religion...go figure. I can see the connection.