That it's all about the players brain getting hay wired so to speak. I see no stories about guys who picked football to play because they liked hurting people to begin with....Some guys get away with murder at a young age just because they show the ability to play a game. They are not stupid and take in the lesson....I am good at this so I will get away with this....it grows from just getting passing grades while really flunking to getting a chance at college and taking that ability to another level....and some get to the pro level and it has been way past anyone being able to tell them a thing.
I know you are into the violence of the game and players committing suicide..or endangering others....but really what pro football players do is just a microcosm of what regular people do in a much larger aspect...and they have not been hit in the head near as much.
IMO it's more like sports stars get special treatment from early on....they get the idea that they are special...it goes from being special to all powerful in several cases..... don't doubt that some players actually have issues from playing the game...but IMO it takes away from them with these other guys who have abused their chance....
That's why IMO it's so refreshing to see that some guys with the "Gift" actually doen't use it as a free way towards life....that take their ability appreciate it and also do well in other aspects of their lives (which IMO are more important)....I like level headed people who are grateful to others and show it by the actions they do in life....IMO it has little to do overall with brain damage....although as I said in some cases it's is true.....