People that placate ethnic groups the way some of those commenters do with Jews are not left wing. If your goal is to form some sort of left wing cohesion, you don't do it by navigating around issues that'll upset those who aren't intellectually left wing, which we want as many people as possible to be (or not?). Because if you do, you won't get cohesion, you'll just get a house of mirrors shrouded in smoke; an unholy alliance for a term or two, if enough planets align in just the right way, that is.

That said, you also don't have to blow too much airtime on issues that might simply not be that productive. If there's a candidate you'd like to criticize who's likely on their way out anyway, there's little reason to spend much on that criticism, unless it's an exemplary proxy for a larger issue. Still, it's a good idea to make some room for it, just to make sure the debate and the field remain honest and clear.