I was just thinking --
White Catholics should be happy when the topic is brought up -- because they should be exempt from most of the "shame" that many white people feel (at least deep down) when racial oppression (past and present) is brought up.
Before the civil war, what few Catholics were here probably didn't own any slaves. In the few cases where a Catholic " owned" a housekeeper or something, they were probably the ones who "treated their slaves like human beings".
But in general, Irish/Polish/Mexican/Italian/German immigrants -- the vast majority of Catholics in this country -- were hardworking people, struggling to make a living -- and were certainly in the LOWEST rungs of the working class. In fact, most Catholic immigrants were discriminated against AT LEAST AS MUCH as those of African descent. There used to be signs "No Catholics need apply." and "No Irish need apply."
All the racist movements -- KKK, Know Nothings, etc. were all protestant groups, usually aimed at Catholics as well as black people (and others). Hitler was an apostate Catholic. (Those are the worst!)
So overall, we Catholics should feel less guilt than just about anyone else. When you learn your history, you see just how true that is.
I would also recommend Catholics learn the FACTS about things like the Inquisition, the Middle Ages, etc. because there are a lot of myths and calumnies about that period -- all of which are calculated to make the Church look bad.