I think it depends how the past is brought up.

You can find, in the past, plenty of material to sew fear, suspicion, and hatred of almost any group.

I don't think bringing up the past for that purpose is very often helpful.

If you bring up the past as a warning of the type of bad actions and the type of fear, suspicion, and hatred that was unleashed then, and use it to find better ways to spread harmony and understanding now, then I think it can be extremely helpful.

Of course, one can use the past in a variety of other ways. But those are the extremes.