I think many have missed the issue. It's not that the players have brain injuries from a violent sport years after playing the game, it's the fact the NFL allegedly had information to know it was probable and either hid it or did nothing to protect players from known risks.
Kidna like the Mcdonalds coffee that burned the 79 year old lady. The coffee was being served at 179 degrees, hot enought to cause severe burns to deep tissue within 2 seconds. Further and most important, there were OVER 700 documented complaint by people who had burned themselves also and nothing was done to address it. Study of comparable restaurants found that they served their coffee at much lower tempertures closer to 120 degrees.