Tamilnadu and Hindi

Why are tamilian's against hindi as third language. Why don't they just consider it as another language like English. Does this by any chance stem from requiring to prove supremacy over central government or north indian states? Also why is there so much of regionalism in tamilnadu compared to other states? I feel it is good for people living in tamilnadu but not to an outsider living in the state. I felt more of an outsider in tamilnadu than I have experienced in any other state. Kerala and Telugu states are far more welcoming in this regard. Any thoughts on this?