I still suspect its a banned poster, that got tired of lurking, created a new dummy account, probably even a dummy email and then had a short fuse at something somebody didnt like that he posted, and then went defcon-5.
They like to think they are anonymous, but unless they are sophistic with VPNs and darkweb crap, then, they leave digital fingerprints behind, compare that to a short list of banned posters, and I suspect you will find your match.