Both of you are right in a sense, but I'm not sure that's the real issue:
1) Yes, casteism is still a serious problem in India. It has by no means gone away, and still continues to blight the lives of many millions of people.
2) However, there *have* been significant inroads made into the problem since independence in 1947. A cultural and social system developed over three millenia, and applying to a billion people is not changed so easily. As has been pointed out, democracy has meant that lower castes control the political process in many - if not most - states. The previous President was a Dalit. And so on. There is much yet to do, but much has been achieved in 60 years.
Having said that, the South African comparison isn't appropriate. Sanctions against South Africa put pressure on the Government to change the aparthied regime, which it eventually did. Aparthied was an artificial legal and social structure created purely by government fiat in the 1920s or so. The vast (black) majority of the populace didn't want it. The Government could (and did) change it by changing the legal structure of the country, although the consequences are still being felt. Hence, sanctions, which directly affect the country and government were effective in forcing De Klerk to do what was in his power.
In India, the caste problem is the result of two thousand years of history. It is not in the Government's power to snap its fingers and make it go away - and at any rate, successive governments over the decades have genuinely been trying to solve the problem.
What will sanctions do? They won't help the situation at all, except to make people in Western countries feel as if they've done their bit for the problem when they've made it worse. It's foreign investment and economic development which lift people out of poverty, and help to achieve things beyond what their caste dictates. If you allow the status quo to remain, then that is license for the caste system to continue..
I was not drawing a parallel between the Caste system in India and apartheid, as practiced and realized by the participants and victims; even in my first post, I was pointing out that the PC crowd in the West (if they were consistent) would be condemning both as one form or another of "racism". Then, if the treatment meted out by the West to the country was at all similar, then *POOF* ! -- greatly reduced foreign investment in India.
Full Disclosure: Please read all my earlier posts in this thread... Cheers!