The nextdoor app originated out of San Francisco so that oughta tell you everything you need to know.
I’ve been put in nextdoor jail and kicked off of it multiple times for doing nothing more than telling the truth.
The moderators are “supposedly” people that live in your area but I strongly suspect the land of fruits and nuts monitors discussions closely....and have no problem sensoring language they disagree with.
No, the actual neighbors report you - tattle tales. The local admins might have something to do with it and can monitor, but my experience, it’s mostly tattle-tales and that gets the SanFran Stasi involved who decide to suspend or ban you.