Just adding my two cents as the original author of the thread which got revived (which was, ironically, about concerns I had at the time about over-zealous moderation).
I think the key thing here is not just that the thread in question was a bit contentious, but also that it had reached a very clear and fixed conclusion, with everyone seemingly on the same page and a wider discussion branching off in the “separating art from the artist” thread.
I think @jasonw22 is absolutely right to describe the resurrected thread as a bit of a special case, that locking it makes sense, and that @Funch’s initial comments would be better off in another thread rather than closed off entirely. Overall, I think the mods have made the right call here tbh.