regards
I'm with you on the "hurt their feelings" angle, but I think that there is a legitimate reason for concern.
An anonymous forum like Factrak does have the potential to unjustly damage the careers of professors, through the dissemination of information or allegations that range from innocent misunderstanding to slander.
Student gets a bad grade, starts a rumor campaign, the electronic equivalent of graffiti vandalism. Where does the professor go to get his/her reputation back?