While I agree with you, you're applying professional athlete logic to a group of 18-22 year old kids. College football and basketball, as we all know, is fueled from emotion and fire. College venues, for the most part, are far more energetic than professional venues and the players feed off of that energy. Now imagine that you're a player getting your equipment on, getting ready to burst through that tunnel and when you do you see...a 1/2 empty stadium. Now I know that the players should only worry about what is happening on the field but seeing a sea of empty seats has to be deflating to a college kid who has busted his tail off all offseason in Coach Balis' S&C program and in Spring/Summer camps.
There are plenty of downtimes during games with TV timeouts, game timeouts and the like. Plenty of opportunity for an excited kid to look up into the stands for his family/friends and see far too much bleachers.