I have posted many times:
Refs have prefs.
And many times their prefs are obvious.
Some were even making up new ‘rules’ on the field last year.
In both sports today, it is impossible to complete virtually any play without an infraction of some kind. So, the refs must selectively enforce or the game could not be completed.
Since selective enforcement is a given, the only issue becomes when to enforce and why. It is a system built for corruption and manipulation.