I agree with you on all the points except the last and in no way I am saying the there are no caste based discrimination in India. In fact caste based discrimination and the effects of it is one of the main reasons of India being "developing country" forever, I think.
My point is that the current rise of nationalism is not because of the caste system, but rather in spite of it. I see many people from lower caste(including my relatives) being active in the local rightwing politics and RSS.