But that's not a social convention, that's a (Corrupt obviosuly) industry convention much like steroids were pushed for baseball and pro wrestling. They're not the same thing at all.
To my knowledge fans were totally fine with enforcers for the vast majority of Hockey.
Not to mention in other sports the more... "Cheaty" aspects are mostly supported by the fans.
Though I have no idea why I am in an argument where I am honestly being told that "Because it is a convention that means it is automatically a good thing! Because it is part of manners it means it is completely genuine... Because you have a problem with it, that means you are automatically an unreasonable moron!"
No, you are saying that sportsmanship means cheating, steroid use and violence, then being told that that's not what the word means at all.
You realize the word "sportsmanship" exists in contexts besides
eeeevil professional sports, right? Children passing a ball can exhibit poor sportsmanship and good sportsmanship, much as can professional players, wrestlers, MMA fighters, e-sports teams, casual LoL or DOTA players, or even somebody playing a single-player game by themselves. It includes concept like obeying the rules of the contest, accepting both defeat and victory with humility, behaving professionally before, during and after the game, and playing to the best of your ability at all times.
You can't just take the word "sportsmanship" and apply it to a specific thing in a specific sport that you are peeved about.