“Many of them may have latent issues from their High school days and this is their way to live them out.”
My guess is that the teachers go for the varsity athletes who ignored them in their own high school days.
I know one female teacher who gushed about the “eyes” of one of her male students. Something about them she found hypnotic and enticing. Again, I don’t think she did anything about it, but a student of hers touched a nerve.
I am sure the same thing happens to male teachers with female students. There is an attraction there, but your moral filters and discipline keep you from doing anything about it. But these days many people lack those filters.