I’m not a follower either, but inference from the article tells me: Krammik has come up with some sort of cheat detection method, has loudly accused some others of cheating, and FIDE are both unconvinced of the truth of the allegations and very unhappy he didn’t do this through proper channels. He also doesn’t appear to have co-operated with the investigation.

one of the players he persistently harassed, Daniel Naroditsky, ended up dying, which surely gave an extra push

His "cheat detection method" mostly consisted of playing someone online and then reporting them for cheating if he lost.