I can buy that cultural issues constitute a point of separation for some people. Others might take or leave various aspects of LDS culture but simply don’t believe historical or doctrinal claims. That seems to be the core challenge for a lot of ex-Saints, particularly in the Information Age.
What does one do when they love their school, are obsessed with its sports programs, yet find that they can’t embrace foundational beliefs on which BYU’s parent organization is based? Grappling with that question and coming up with a workable path isn’t particularly easy for a lot of folks. As you point out, it’s nice to see so many remain dedicated fans of BYU sports and/or maintain their fondness for their college experience.
Some of our most-legendary squads have featured tremendous diversity among our top players—look at 1980, with Jim McMahon leading the way and future GA, Vai Sikahema scoring a crucial TD in The Miracle Bowl. It makes sense that the fanbase can house a wide range of beliefs with a core common passion as well.