The Hindutva ideology — distinct from that of Hinduism which stresses ideals of brotherhood and Vasudeva Kutumbakam (“Though nations might be mired in conflict, civilizations co-exist”) — was given a political by Vinayak Damodar Savarkar when he formed the RSS in 1925.
To really get to the heart of India’s recent majoritarian turn, a look into the ideology that drives such hatred is necessary.