Sorry for bringing back an old thread, but its an interesting topic.
If I had to pick one i'd go with rugby LEAGUE specifically, but I dont think theres really a simple answer and obviously people tend to get defensive and tribalistic about it usually based on whatever is the "tough" sport of choice where they live.
Hockey clearly has the highest POTENTIAL for brutality. When you take into account the skates, the sticks, the puck, the ice, the boards, the speed and obviously the lenience for straight up fist fighting in the middle of a game. But there is a big difference between the extreme end of what happens vs what the average player typically goes through in an average game, and overall hockey players are not taking the same level of consistent physical contact as rugby and American football players. If they were they wouldnt have the strength of schedule that they do because it'd leave you in a wheelchair before long. Another thing is overall they are a lot smaller than rugby and American football players and just generally not so much in the "freak athlete" vein because its more of a skill game. A big intimidating dude in hockey is just a regular dude in the others.
With American football theres is so much variation between positions that the kind of brutality you're gonna face is heavily dependent on that. A QB or kicker isnt getting much of anything compared to any position in rugby or hockey, but then if you're an RB or one of the linemen for example you're going to be dealing with explosive high impact shit on pretty much every play and fast tracking yourself to CTE. The hits are on average harder than rugby as well because the helmets and pads embolden players to just throw themselves headfirst into things at full speed. Theres also much more likelihood of getting blindside hit or just generally hit while in a shitty position.
Rugby Union the hits arent as hard but the contact is much more consistent and the threshold for getting hurt a lot lower due to the lack of helmets and pads. Its basically high speed team wrestling mixed in with a ball sport. Theres a gruelling, grinding. down in the trenches element to it that the others dont have to anywhere the same degree.
Rugby League the hits are often coming at higher speed than union and the game is easily the most relentlessly fast paced of the "big dudes fighting over an egg shaped ball" sports. Unlike union and even more so American football, there is barely any downtime. Its pretty much run full speed into a wall of players, get put on your ass, get up, roll ball back, repeat, for 80 mins. The amount of tackles made etc in one game is ridiculous.
