I don't necessarily think that's the case. Remember the old "nobody on the internet knows you're a dog" cartoon? Well, I think that for a lot of things, nobody cares if they're talking to a dog.
People only care about people on the internet being fake in certain contexts. They'll very much care if all of their dating app matches are robots, because the end goal of a dating app is actually meeting someone in the flesh.
But I don't think that people on Nextdoor and Facebook groups particularly care - or would even notice - if they're talking to robots. As far as I can tell from my limited exposure, most people like getting caremad in comments. Even in local groups, it doesn't feel like there's much connection being made between neighbors; an AI complaining about traffic or agreeing/disagreeing with someone's political opinion would scratch the same itch as someone two towns over doing it.