But we agree there was no India to ascribe this non-invasive nature to, before unification. With the result that India-as-a-whole is the product of aggression against neighbors, where all those neighbors became India, but only quite recently, meaning that there hasn't been much time for India as a whole to be aggressive against further neighbors.

It's like saying that the English never invaded anywhere before 927. Of course they didn't, because the first English king was crowned in 927, and before that the English were the West Saxons, South Saxons, East Angles, Middle Angles, South Angles, Men of Kent, two flavors of Northumbrians and a few stray Welsh, and they were all busy invading one another.