You are aware that there exist nasty people? People who take pleasure in inflicting pain? That's the simplest hypothesis. There's no need to lurch into dark conspiracy theories without any supporting evidence.

I dunno, the "meth party" hypothesis elsewhere in this thread seems pretty simple/plausible also.

If you ever own a rent house, your paranoid fantasies will evaporate the first moment that you have to scrub shit off the kitchen walls.

It's not part of some big plot to ruin AirBNB. Some people are just assholes.