Irrational, but not _unreasonable_. It is, after all, the campus' property, and if they want to include vapes in their smoking ban, they can do that. That said, however, if its a vape-only ban, I'd complain. In epic proportions.
I vape all the time at my college (not in class, though, lol). But, it's mostly engineers, so the quick explanation of "a nichrome resistive element used to vaporize a glycerin-based nicotine and flavorant solution" is usually met with some kind of nerdgasm. Campus safety asked me what I was smoking once, I explained the inner workings--he just shook his head and walked off.