Saying that they all do it (cheating) is not saying that that makes it right. It is all in trying to get the high ground over an opponent. As the Apostle Paul wrote, when you condemn someone for a particular behavior that you also engage in, you are condemning yourself.
So getting the high ground makes it right? You are merely rewording the problem. AND YES claiming that everyone does it is an attempt to justifying it. Maybe you like to discuss what the word is is now?