It is from Ugo Bardi. He has been a few times on page one on HN. A well known scientist from Florence.

Maybe someone's Ai agent was given a task -> Delete people whose name starts with "U"!

Joking aside, this stuff is happening on all social media; first some unknown entity hijacks the session IDs and then they delete accounts and the social media overlords don't give a damn. I think you should scan your computer for viruses anyways.