Nextdoor appears to facilitate neuroses in isolation, which was not the case with public meetings.
That's a misguided instinct when the people you are talking to live two doors down. Get a handful of people who see them everyday to say, "knock it off", and they usually will.
Years ago, I had a couple of neighbors I'd talk to, but they all moved away. Had a few friends I talked into moving to my complex too, but they've all moved away as well.