I've had friends my age, much older, much younger, I've been in relationships with girls much older and much younger and the same age, and for the life of me, I cannot figure out why you think that something like age difference would be a factor in messing people up emotionally

It seems like they could get even more emotionally damaged from someone who is inexperienced in relationships, but really, I'm pretty sure that getting messed up emotionally from relationships is not exclusive to people who have differences in age.
Also not sure about this whole predator/prey deal, I'm pretty sure there is no animal that has ever existed in the universe that wanted to be eaten by another animal, yet I'll bet this guy wanted to have sex with his teacher regardless of her power or status.
The only part I agree with you on is that a student/teacher relationship is not conducive for excelling in a school environment (besides possibly getting a good grade undeserved). So ya, the teacher should probably be fired, and they probably shouldn't be having relationships with their students. Or at least wait. Just be like, hey, when you graduate we can start dating. But to assume that the teacher is a bad person, or that they should be in jail, or that they are some kind of predator just doesn't make sense to me.. I mean, it's all very possible, just not something that you can conclude from what happened.