The Romans had the Assyrian brand of "object lesson" policies down right well far as I know. How about the intentional brutality they engaged during the capture of Greek cities for the purpose of intimidating the rest into submission ? Hardly an uncommon practice of course, but that sort of stuff was the standard Roman policy. Or the "cautionary example" mass executions à la the crucification of the survivors of Spartacus' bunch, or the assorted ghastly masscres inflicted on the Celts ?

Sheer brutality was a tool they had not the slightest compunction about using as a weapon.

As for the culture thing, one gets the impression they had the same kind of inferiority complex towards the Hellenics as the Hellenics had towards the Persians and other Near Eastern high cultures - they admitted the undeniable and readily observable achievements easily enough, but claimed moral superiority.