Hoo boy. /me puts on his
asbestos suit.
I think a better name for the "Your people oppressed my people, shame on you" attitude is reciprocating racism.
That is, at some point my people were racist to your people. (I'm a white male, so this is probably true, even if your people consists of, for instance, small amphibians named Fred.) Therefore, your people reciprocate and are racist in return. Nasty cycle, eh?
In Reality, though, I've not seen this very often. The kind of people who tend to pull this are generally off kilter in other ways, too, and I can easily ignore it.