I think it’s more like “don’t publicly stand for political violence towards fascists because their base is unhinged and you bring the violence on yourself”. Also, the violence has given the fascists power. Right now, the dems defense has to be damage control. I know many people wish Trump had been taken out (especially by another republican) but it didn’t happen, most likely won’t now, and dems need to put on a “we don’t condone violence” face so they can maybe try to win.