I downvote because, unfortunately, average people love insults like "low IQ," "b!tch," and many other things that modern socialists find unsavory.
At a certain point we are hurting our own movement by trying to be PC.
There is also no definitive line we draw. You may say that line is with "low IQ," but someone who claims to be woker than you will say that the origins of stupid, dumb, idiot, moron, etc. are all equally ableist.
Not to mention, we absolutely should be taking an opportunity to impune our enemies as stupid, or as useless/cruel (whatever the implication of "b!tch" was in whatever ya'all are referring to), because, well, they are.
Unfortunately, people will often respond to a dunk better than a graph.