Of course it's correct. All thieves try to hide their traces, right? It would be stupid to steal and to not care about leaving traces leading to you. /s
Stole people words/content aka plagiarism is theft, but for me it's not something that lead to negative feedback. It's a matter between him and the moderator, not for us as a member.
I'm not going to say you're wrong to think thieves try to hide their traces, because you're correct in your side since you're the one who get involved with him.
Why would having one's posts deleted affect anyone other than wasting the time of the person who wrote them? In any case, that's always the chance you take when you post in a self-moderated thread, right?
It's true, but I think people aren't expect that since he's a Legendary user, familiar with this forum, and has a good reputation, so it's almost impossible for him to troll the forum members.