Why are principal characters typically 'evil' in kids' shows?

[TMC]

http://officialfan.proboards.com/thr...evil-kids-show

I noticed a trend in kids shows, that principals, vice principals and other school administrators are boarder-line "evil" in kids shows now a days.

I don't mean just antagonists because they try to foil the kids schemes and don't let them do what they want like Mr. Belding, but I mean evil like "why are you in this line of work, you clearly hate kids" that type of evil. Granted not exclusive to this generation, the Vice Principal from Welcome Freshmen he definitely didn't care about kids and education, but now a days it is just evil school administrators who don't belong in this line of work, like the principal in Lab Rats, she clearly hates kids and she is as corrupt as a politicians, how does she keep her job?

Shouldn't the message be to kids, that teachers and principals that while they might discipline you at times, they are still your allies. Not they are out to get you, they are as bad as the school bully. What happened to the days or Mr. Belding, he maybe have a dork, he may have often trying to foil Zack and the gang's plans of fun, but you know he cared deep down, he wasn't villain, like the principal in Lab Rats or the principal in that Nickelodeon about witches they ran last month.