Rate My Students?

Here is Astroprof complaining about bad student excuses. The stories are pretty amusing, I guess. But, I have to be honest, I'm uncomfortable about so many teachers putting their "aren't my kids lousy?" stories up on the Internet. It seems fairly hostile. I mean, we've all had students do some dumb things, but so what! They are 17 years old, after all. I can't imagine how I would feel at 18, if I went on the Internet and heard some professor bitching about something stupid that their student had done, and recognized myself in the story.

But, more importantly, shouldn't the common courtesy and manners that we want to instill in these kids be based in some sort of mutual respect? What does it say to the students when our contempt for them, even if it is based in a deep disappointment, is so thinly veiled?