These aliens are demons and Hindus are literally demon worshippers. The Aryans that conquered the Dravidians (subhumans with Denisovan admixture) worshiped the Asuras and saw the Devas as demons in the original vedic oral tradition. There were initially only two castes, the Whites (Aryans) and the Blacks (Dravidians). Half-breeds would always fall under the Black caste to be used as soldiers or slave labor.
As everyone knows, race mixing never ends well, and when enough half-breeds were created, they rebelled against their Aryan forebears and adopted an inversion of the original religious system to piss off their pure-blood fathers, corrupting the vedic traditions and forming Hinduism. And so they would worship the Devas and hold contempt for the Asuras. Not unlike how edgey Satanists pretend to worship the devil in Western Christian soyciety today.
Eventually, total war would be waged in major rebellions and the Aryans decided they had enough of the subhuman monkeys and decided to leave them in their own filth and depravity, returning to their folk in Persia. The original belief structure is preserved in numerous Western pagan religions. In Persian mythology, the Ahuras (Asuras) are the pantheon of the Gods, and the Daevas (Devas) are the demons. There are also hints of the original structure still preserved in the Mahabarata where the Asuras are the good Gods of creation and the Devas are antagonistic and evil.