Not entirely sure it's a position he should be making out to the news, but its far from "wrong" in its concept. However he does seem to take it a little far with the explanation, making it seem awfully sleazy. All people who work in any workplace with attractive people are going to look and admire, and consider themselves lucky. Its an unspoken thing, speaking it (or making it obvious to the other workplace people) may make it uncomfortable and isn't right, regardless of the workplace in question.
As for it not being an abuse of power, im not convinced on that one. While there's certainly nothing legally wrong with dating a student, it is seriously frowned on (but certainly not unheard of). In technical fields you can't easily change marks or affect the direction of the students without someone noticing, it is very well checked and balanced, but in some of the arts degrees it is pretty obvious that it's interpretation and the marks are given based on the staff viewpoint, plus it would take considerably longer to work through the answers etc to prove wrong-doing.
I dont think many of the students could be considered any more vulnerable than any other young adult, so that argument doesnt really fly with me.