I've taken in my share of college football games are at different venues, and BYU is about as hospitable place as you will find.
While we are not perfect, we put a lot of kids on the field who play hard and with good sportsmanship.
The problem is, BYU holds itself to a standard and is not shy about proclaiming this. We are also a largely conservative school in a time where being such it's not popular in academia.
People absolutely love to tear down folks who have announced that they are trying to do something better or achieve some standard, particularly if they have some reason not to like them in the first place.
There will always be those that jump at the chance to try to take down BYU and/or make them look bad. And unfortunately, there will probably always be a lot of people who buy it--especially when BYU happens to beat their school