170+ comments in a day is not simply 'arguing about politics'. Even then, though, not every community or instance allows just any kind of arguing, and not every mod will tolerate a flood of reports about a single user arguing just a bit too aggressively. Especially when the specifics of the argument are borderline rulebreaking by themselves.
We seem to have moved the goalsposts from “he’s abusive” to “he was banned from blahaj which as everyone knows means he definitely actually did something” to “he argues about politics how dare.”
Sorry, who's moving the goalposts? You accused the admins of 'harassing' him, then backed down to 'unfairly singling him out'. It would be impossible to 'single him out' any more than he has already distinguished himself by the shear volume of his activity. A one-off heated comment is very different than dozens and dozens.
I am aware of your personal political alignment with PJ, so I understand you may identify with the content of his commenting - but the shear volume of it is enough on its own to warrant intervention.
It's only a temp ban, anyway - a glorified time-out. I'm fine with leaving it as a disagreement.
PJ listed 'sexual assault denier' as the reason for the ban, seems pretty clear that - at the very least - this interaction was top-of-mind when he was issuing it.
This is the thing I'm pointing to as a pattern with him:
Whether or not PJ went into that interaction knowing felix's intent is hard to say, but it should have been clear to him by the end that there was no actual disagreement being expressed. In the end, PJ mis-represents the source material and doubles-down on his accusation of SA denial in his ban reasoning in the modlog. An interaction that should have ended in clarity instead ends in him banning the user, if not for the stated reason in the log, at-best for downvoting posts in another comm.
It's a pattern with PJ that he dives headlong into an argument making an assumption about a user's intent, and then when the user clarifies their position against his accusation, he doubles-down by either misrepresenting that user's statements or by twisting source material to fit the accusation being made. By the end of that argument, all he's doing is accusing felix of lying by mis-attributing the source material he's using. He's being unnecessarily hostile when, in the end, there wasn't an actual substantive disagreement between them.
He's a prolific poster/commenter and a mod of probably a dozen communities. I don't care about the history comms he spends a lot of time in, but I do often see him pop up in political gossip/snark communities like 'tankyjerk' and 'meanwhileongrad'. Most of his original content he posts is fine, if not good - but he often gets into it with other users on politics and does exactly this kind of rage baiting, occasionally posting it to the political snark comms if he's worked up enough about it.