The world has gotten WAY too politically correct.
If a high school (or middle school) teacher chastises a student in class, they run the risk of having the exchange digitally captured and placed on the Internet. The problem is, the events leading up to the video clip are rarely included in the initial showings. People jump to the worst possible conclusion, generally egged on by the people who uploaded the video. The resulting fall out can ruin a person's reputation and destroy their career. Don't get me wrong, sometimes a teacher's behaviour needs to be called to task, but there are official channels for that type of thing.
Stitchawl, there are teachers out there who have/had no business ever being in the classroom. It's a shame how often those are the teachers who stick out in our memories the most.