If the tradition of beating up the Tom Landry Middle School mascot was so well known, how come Bobby didn't know about it ahead of time and why did no one tell him? Also, why are the adults okay with a kid getting beat up considering the physical damage that could happen?
Well, a recurring gag in this series is characters taking football games WAY too seriously, sacrificing common sense to uphold traditions, regardless of how outdated or dangerous they may be. The series paints a satirical look at sports fanatics and this was done intentionally to highlight how absurd things often get.