I'm going to have to disagree with you a little because of the specific example you've cited.
As one of these teachers slept with an 18 year old student, I'm assuming these are final year students who are months away from graduation. I know it's (very) different in the USA, but here in Europe, if a 30 year old, moderately attractive male teacher slept with a final year female student, there would not be a witch-hunt and he would probably not go to jail; he'd likely get probation and a life-time ban from teaching. A woman would receive the same.
We're really in a grey area with this example as the teacher is quite young and the students are above the age of consent in most parts of the world. In virtually every other situation but this one, there would be no issue whatsoever. And that goes for both men and women.
I realise (and would hope most people do too) that a line needs to be drawn somewhere but this specific example merely has its toe over it. It is just not comparable to a 50 year old teacher molesting a 12 year old. In cases like that, yes - we clearly have predatory behaviour and no possible way the victim consented. But to suggest 17/18 year olds - male or female - cannot make decisions for themselves in these situations is honestly quite condescending.
Like many people, I had already graduated from school and was working in a bar at 18 while I attended university. I slept with a few customers around the age of these teachers, knowing full well that I was taking advantage of them being easy and not able to hook up with someone their own age. I would have been grossly offended if anyone suggested that I was a child that an adult was taking advantage of, as I'm sure a lot of people the same age would be. Which is why you are seeing the Facebook comments you are seeing.
To me, these comments are not proclamations that someone doesn't have ownership of their balls. In fact, I would say even the complete opposite is true. These guys, if given the chance, would like to fuck a woman that society has deemed untouchable. What's wrong with that? Half of the posts on this sub are about men wanting to attain the seemingly unattainable.
I, for one, would support a 17 year old dude who wanted to fuck his teacher, providing it didn't affect his grades or college admissions etc. just as I'd support a 50 year old dude who wanted to bang a hot 20 year old, providing it's not going to wind him up in jail. I would definitely have done the same thing in the same circumstances so yeah - "where were these teachers when I was in school?"