Was Ambedkar anti-national for attacking Hinduism?
He attacked a social order, not a country, and he was careful to keep the two apart. His argument in Annihilation of Caste was that a society divided into a hierarchy fixed at birth cannot become a nation at all, because a nation needs fellow-feeling among its members and caste is designed to prevent exactly that. On his reading the criticism was the patriotic act: a people who will not eat together, marry across the line, or fight as equals is not yet one people, and saying so is not an attack on the country but a demand that it finish becoming one.
He also refused to let loyalty be used as a gag. He held that a citizen owes the state obedience to its laws and owes the society nothing but honesty about its faults, and that the man who points at the crack in the wall is not the man who put it there. He worked inside the state's institutions for most of his life — Viceroy's Executive Council, Constituent Assembly, first Law Minister — which is a strange record for someone said to be against the country.
What he was against is stated plainly and repeatedly: a graded inequality he believed weakened India from within and would keep weakening it after the British left. Whether his diagnosis was right is a real argument. Whether making it was disloyal is not one the record supports — he spent his last decade writing the rulebook the nation still runs on.
In the Journey: The speech that was never delivered, 1935–1936