Does something surprise you? This is an ordinary useless forum troll who sits with an alt account. He is scared to present his main account due to his cowardly nature. Most of his words can be safely divided by zero, since they have no basis whatsoever.
I didn't know him and I've just recently seen the feedback you left him (neutral btw, was that negative changed to neutral?).
I would advise these 2 users to just go through the history of their posts, and find all possible omissions themselves, so as not to continue to feed the troll.
In this I do not agree with you at all. You are basically telling two criminals to hide the evidence of the crime. If they have plagiarized repeatedly they don't have to delete the evidence, what they have to be is banned from the forum, which has already happened in at least one case, and never come back, as the rules say.