Was a good read, thanks OP.
What a bunch of nonsense. Combat veterans, police officers, firefighters/EMTS endure much more.
I don't see the connection between a contact SPORT and domestic violence.
Difference I see there is all of those jobs you listed are "heroic" jobs, where protecting and saving society is great motivation.
Obviously those jobs are 10x more challenging and gritty to cope with as a profession than pro sports, don't get me wrong and I don't think anyone would disagree with that.
But in a specific way, I think playing football for a living is actually More difficult for that very reason. It's Just a game, nothing more, nothing less, yet you're asked to go 200% with your body in all kinds of very dangerous contact.
To save people? To care for others? To defend a noble cause? Nope. Just to play some game and hopefully get some championship for a city's fans.
It has to wear on your brain and body after enough time that you're breaking yourself down for a really selfish, entertainment-based reason. It's for fame, glory, and money.
And IMO, when players have turmoil in their real lives that affect that fame/glory/money they busted their tail for, I could see that trained aggression and shrugging-off pain as go-to methods for dealing with people in your life.