Good point. But pose the question to them: suppose it did happen and ask them if violence is good? Try to cut through the BS and if they still don’t believe then offer this “there is little hope for the future of this country when people are willing to be violent and others are willing to cover up that violence.”
But that’s just it. Whenever you mention these actions to some liberal acquaintance, they deny that it even happened, accuse you of lying and making stuff up, or getting crap stories from far right wing nutcase websites. All because they didn’t see it on their precious MSM ‘real’ news outlets.
They will evade any logical reason to debate the matter because ‘their side doesn’t do such things’ only nazi-right-wingers do...................