They could attack the non-steelmanned version, but that just opens them up to having their own comments attacked. You quickly get derailed. (It's sometimes called "sealioning".)
They could propose alternatives, but that too is subject to sealioning. Real alternatives are always subject to tradeoffs, and the answer to "how about you do X instead of attacking me?" is always "no".
They could refrain from discussing it, but that just allows the offenses to continue.
So what often happens is that people persist in acting as if this were a sincere discussion, and hope that a majority will recognize the quality of your argument. It's a lousy plan but I don't have much else to suggest.
As you say, that's exactly what got us here. But the alternatives are very unclear, and seem deeply unpleasant.