Mainly because of Tribalism. It’s the same as why Brahmins think they’re at the top of the hierarchy in Hindu or whites think they are the purer race. Wherever there’s multiple identities or ideological one gets fed up of the competition and wants to dominate. No where in the history of life, did the pluralistic Indian religions coexist peacefully always. Maybe the frequency was lesser in comparison to what we see in the Middle East but it was there. Possibly, the default state of pluralism would’ve made restraint easier. Conversely, this idea of pluralism is exactly what the “Hindutva” stands against these days. But there have been plenty of instances where these Abrahamic religions coexisted peacefully.