Well that's all well and fine, but seeing that he isn't actually the source of the problem, only a part of it, i fail to see your point?
And it doesn't change the fact that your intention with the message was to make him feel bad, which is shitty and disrespectful, no matter how corteous you were. I have also yet to understand how making him aware of the "errors" of his ways would stop anyone else from doing the same thing? Do you think that these people all know each other, and that he could somehow effect others "planning" to do the same thing?Come on, leave the kid alone, you basically come off as a vengeful douche, give it up.
And why would you go through all of this effort to bother him, only to apologise afterwards, that makes no sense?