The lobbing accusations of abuse back and forth during a simple breakup feels like a common poly community thing.
Counter or additive point, though yours is a good one - I believe it's a terminally-online thing rather than a poly thing. PL, but I've spent some time observing similar or adjacent circles, both mono and poly, and every broken-up relationships end up with abuse accusations,
without fail. Remember, these people live on the net. Their interactions are purely based upon pseudo-social relations where you only have words on a screen. No action, tone, context, or gestures to go off of. And they spend a
lot of time in this environment. You haven't texted me for a while even though you have a life outside the net? You're abusive/emotionally unavailable. You've misunderstood something that comes from the inherent quality of talking on the net? You're gaslighting. Had I forgotten a piece of information that I would have otherwise remembered if you told me this in real life than online, and did something that inconvenienced you? You're purposefully triggering me and therefore abusive.
The abuse accusations and other slander is them trying to make sense of a mode of interaction that is missing key aspects of a physical interaction. I think what makes them exceptional from regular people who met online and dated afterwards without issue is the fact that they're
terminally online.
Plus the Cluster-B black-and-white thinking (EDIT: as Stupid Sexy Flanders mentioned before me). You're either a good partner or you're abusive, extremely awful, isolating, emotionally unavailable, manipulative, and purposefully set of my triggers!1!1!1!1!!1!1
