Rules of boxing?

Let me get this straight. In every sport there are rules that every participant needs to abide by. If a participant breaks those rules they get warned, fined or penalized right? I want to know how in the hell does Henry Aikinwande get disqualified for constantly holding Lennox Lewis in their fight, however, Ruiz is guilty of the same rule breaking in every one of his fights yet has never been disqualified in his career. Now tell me this, as a boxing fan, how can you get excited about anything this sport has to offer when you know that there will eventually be a scam that fucks a boxer who works their ass off to try and win. This decision has made me sick to my stomach.