Another take is that sports are all about rules. The goal of hockey isn’t just to get the puck in the net. There are other rules that turn this minimal task into a game. Otherwise players would just come on the ice and fire the puck via a rail-gun. To make an entertaining sport you need a goal and a set of rules that make and interesting challenge.

To some degree if you allow performance enchaining drugs at least some of the focus moves away from physical skill, reactions and strategy into pharmaceuticals. Don’t get me wrong, finding the best drug cocktail to play hockey is a very interesting challenge, but it seems interesting to a very different audience than that which appreciates the other aspects of the challenge.