Aaron Hernandez in most peoples eyes, is that he is guilty. I think he is taking this situation very lightly and really needs to be more professional. I know he is rich, even though he is in jail, but you need to understand that money won't buy your way out of what you have possibly done. Act like an upstanding person and take the fun and games to your cell if you must act that way at times.
Aaron must display appropriate conduct before a judge who is in a position to make a decision on the future course of his life. His demeanour could mean life or death. If the court or jury get the slightest indication that he is not serious about the court proceedings it is very likely they will rule against his favor. This argument may sound trivial but it is - unfortunately for Aaron - a resounding fact. Persona can influence decisions.
Aaron Hernandez claims he is innocent. If that's the case, he should act more humble so that jurors and peers will believe him. When people act rude, they tend to not be trusted. There is a lot of evidence against him. If he is guilty, he needs to be humble to show sympathy.
The jury is there to judge his guilt or innocence in a murder trial, not judge his personality no matter how vile it may appear. They don't have to like him, they have to assess the facts about the crimes of which he is accused. Hernandez is a jock and most people have some experience with self-aggrandizing athletes. His behavior in court probably won't affect his case either way.