Dalit (the oppressed one) is not an insult. Ambedkar (a key Dalit emanciptor) uses the term 'Dalit' as a badge of honor. Insulting words for low caste people would be 'chamaar' or 'harijan'. Dalit is the official word for castelesss people in Indian Law. 'Dalit' is not a personal attack. It's like 'African-American' or 'Hispanic-American' as opposed to 'nigger' or 'wetback'.