I happen to used to know Angel a little. Prob not my favorite guy, but he's ok. I do know that he is considered one of the best refs in the nation. They do have a ranking system. I am a ref and his positioning and mechanics are excellent. There is a lot of subjectivity in the sport, and I think that is part of the issue. Also keep in mind that most fans and coaches don't know the rules. I know for a fact that the Flo bros and Ben Askren do not understand NF criteria, because I have heard the talk about NF multiple times. (For example Antrell Taylor vs Downey at CKLV). So this likely adds to the problem.
The Sealey no-takedown call was bad.