It's really not that hard to understand; some people just feel more comfortable one place vs another. I don't pretend that USU is a better school but based on my chosen career path that wasn't a huge concern so I wanted to go somewhere I felt comfortable, which was Logan.
Not sure how many others like me there are but I doubt I'm alone. And yes, there are a lot of Aggies who are only Aggies because they didn't get into BYU (my wife is one of them).