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.