All religions proscribe ways of life to their adherents. Hinduism just happens to be incredibly complex. You are right though that it is perhaps unfairly lumped together (some sects anyway).
Southeast Asia would've liked remained Hindu had it not been for the simultaneous expulsion of all Buddhist elements from the states throughout the 1000s (mostly via. Muslim conquest) and the eventual ascendancy of Islam in the region. Trade with India and the West was always important via. the Straits, but when Arab and Muslim Indian traders began to dominate it, there was no reason for God-Kings in Cambodia and Sumatra to remain so. Some sort of continuing powerful Hindu Indian Empire would probably prevent the conversions that happened iotl and keep Hinduism as the major sort of faith in the region (though I think it might just be a plurality, not a majority).
Hinduism is a way of life, not a religion. It was only considered a religion when colonization occurred. Calling it a religion may insult some Hindus.
Southeast Asia would've liked remained Hindu had it not been for the simultaneous expulsion of all Buddhist elements from the states throughout the 1000s (mostly via. Muslim conquest) and the eventual ascendancy of Islam in the region. Trade with India and the West was always important via. the Straits, but when Arab and Muslim Indian traders began to dominate it, there was no reason for God-Kings in Cambodia and Sumatra to remain so. Some sort of continuing powerful Hindu Indian Empire would probably prevent the conversions that happened iotl and keep Hinduism as the major sort of faith in the region (though I think it might just be a plurality, not a majority).