Society's definition of abuse is mainly physical. If we can see a slap or a punch, we can replay it over and over, analyzing every move. We have concrete evidence of who's at fault and who's the victim. When it comes to mental abuse though, there is rarely evidence.
From my perspective, young athletes are some of the most vulnerable people to work with. They have dreams of college and the future, and they will do anything to get there. They haven't seen life for what it really is and will trust most people.
What happens when a coach dangles the carrot of future success in front of an athlete's face is that the coach feels like he has the liberty to treat the athlete however he wants. They could mentally and emotionally abuse them, justifying it with, "I'm the only person who can help you get that scholarship."
When coaches tell athletes, "You're being selfish," or "You're making excuses," they are reaching the heart of the player. Instead of critiquing their game, they are going straight for the kids' character. After practice, that kid may doubt himself, which will make him play worse during the next practice. After a few bad practices, a coach may divert his attention to another athlete who he says, "has the passion and drive." In reality, the coach initiated it all along.
I've seen this scenario play out in the workplace, too. A manager or boss will subtly manipulate the employee into thinking he is wrong and a bad person. When that employee's confidence slips, that's when the manager blames the employee for not "being positive and hard-working." This is happening all across the world right now to thousands of athletes, but they don't know exactly what's going on. They know something is wrong, but they can't put their finger on it.
If you look around sports, you will see coaches getting fired from different schools for "mentally abusing their players." On the outside, one may think, "Oh, that's not real. The athletes need to suck it up." But in reality, it's more real than being punched in the face. A bruise or slap will heal. A young athlete hearing that he is "selfish and not good enough" will last much longer. I can still hear the terrible things my high school coach told me, and I've been out of high school for years. Honestly, I'd rather he punched me... the pain would only last for a minute.
The problem with mental abuse is how subtle it is. I had an AAU coach growing up who would curse at us every practice, but he did it in a productive, improving way. We would deal with the curses because we knew, deep down, he wanted the best for us with no ulterior motive. He was getting us into shape and we appreciated it.
My high school coach was the opposite. He was thought of as a legend in his little town from his history of success, and nobody would challenge his authority. This gave him free reign to act however he wanted. If he didn't like a certain player, he would not play them, and that player would be forced to attend another school to get playing time. The parents who sucked up to him were shown the most attention, and their child would get the most minutes. In the end though, many players hated playing for him, and plenty have said he destroyed their passion for basketball.
Young athletes are scared to talk about mental abuse, and parents have no idea how to handle it. There's no physical evidence, and phrases can be altered to mean something completely different than initially intended. There are no official laws against it unless it's taken to an extreme. A coach will get fired for punching a player in the face, but nothing will happen when they subtly abuse their hard-working, trusting athletes for years.
Once we start to address this issue, that's when change is able to occur.