"Loose cannons". They're not exactly notorious for their brain power. Males who gravitate towards physical sports like rugby, football, boxing, MMA are not your regular medical student which is why probably less than 1% of former college football players are Medical doctors.

Point is, in order for Buck and the thousands of other successful college and pro football players over the years to be successful many of them almost had to have a few screws loose. You don't typically gravitate towards physical sports like that unless you have some level of chemical imbalances.
It's not exactly normal for people to want to run into each other at top speeds right?