During the vedic and the puranic period, the ancestors of hindu nation had to fight the Daityas, danavas, raksasas, the cruellest, most atrocious and cunning cannibals of the time.
To fight crafty enemy with super-craft ,to destroy barbarism with hyper-barbarism, as the only effective means of annihilating the foe, was the praise worthy principle of religious warfare of our god-like emperors till at least the close of puranic era.
We need to follow that expansionist principles of our god like emperors with the motto " kurbantu viswam Aaryam " which means" Lets make the world Aryanised "