I think this action was not very nice. Michael Sayers might be feeling terribly upset about all this now.
(Of course, when he was active on PS, he was more eccentric than we'd've hoped, but still, it is mean to make fun of him like this. "Michael Sayers" might feel despair and hopelessness. If "Michael Sayers" is his real name, then I think he might feel that his reputation is lost, and he must start a new life. )
Telling someone that they play the piano terrible may be very hurtful to their feelings, even if the comment was made in jest. Especially when the victim of the jest has been studying the piano for so long, it can make him feel hopeless, empty, lonely.
When he has been playing so long and (hopefully) delighting in the piano, and then dozens of people come up and tell him that his playing is ugly, retarded, and distasteful, what do you suppose he feels? As P. Wilkins said about a ancient Chinese poem, "words can barely describe this sadness." *
Well actually, I made that quote up. And a poetry-critic named P. Wilkins doesnt exist. LOL. But you get the point.