Media is a joke. Someone had to bring up, "he was messed up from football/brain injury". Why are mostly football players the violent, law breaking athletes. Boxers get hit 1000x more and you rarely hear similar violence.
Football just breeds this kind of personality.
Ironically, a not insignificant number of D1 NCAA and NFL players go on to become physicians, mainly ortho and EM bros.
Boxers also do violent things. But the public can't name 5 current boxers, and some washed out, unknown palooka isn't going to generate media attention. However, "former NFL player" applies to tens of thousands of people and that label attracts public attention even if that person is an unknown.
Also, professional boxers incur way less concussions in their 20s than college and pro football players. That's kind of the #1 requirement of making money in the face punching business -- the ability to see and defend shots, slipping and rolling with punches. Boxers' CTE shows up after decades, when they're too old, infirm, and demented to hurt anyone.
Maybe this guy was a scumbag, maybe it was CTE, or both. Who knows? I work with a number of TBI cases, mostly from an MVA, occasionally an assault or history of sports concussions. These are previously super high functioning people (educated, professionals, etc) with no history of violence who are now basically 2 year olds with zero impulse control when off meds (i.e., beat their parents to a pulp for not giving them candy, masturbate and defecate in public, etc).