These people are not upset over a flag, or a monument because of slavery. If they were then they would not vote for the party which did slavery .
Just because you remove all vestiges of history doesn’t mean it didn’t happen.
It just extends your ignorance.
If they were upset by slavery, what are they doing down here in the South? Wouldn’t that trigger them every single moment of every single day? Would their delicate constitutions be able to handle living in the South?