In France, Spain, Italy - they speak Latin, they are nominally Roman Christians. In North Africa - they speak Arabic, they are nominally Muslims.

I'm not talking about physical destruction, physical genocide, I'm talking about a massive cultural shift, where the previously similar people in Carthage and Rome have become cultural divorced. That is the destruction of the Roman Empire, not episodes of mass-burnings.

I'm also talking here about cultural memory, not historical wars. Ask a Spaniard about the Reconquesta, or a Greek about Hagia Sophia.
I speak English near-fluently. Doesn't make me an Anglican.

Yes, a massive cultural shift did occur, but it took centuries upon centuries. Also I don't buy into this whole "cultural memory" concept, which sounds pretty arbitrary to me.