because we are talking about perfectly trained adults here, they are the players and I would guess that they now exactly what is best for them and what is not.
This is just like people saying that they want a no helmet law when it comes to riding a motorcycle. These perfectly intelligent and trained adults know the risks. So there should a no helmet law right? If someone gets into an accident and has a head injury which puts them in a care facility for the rest of their lives, they will be going after the insurance company, the driver, the state, and everyone else they can get money from.
The problem is that these hockey players are going to be fine with it until one of them takes a stick to the eye and then their career comes to an abrupt end. Like Manny Malhotra who has played in 9 games since his eye injury and it looks like his career is finished. He is going to get as much from NHL disability as he can.
There are times when people must be protected from themselves. Just like people should be forced to wear a helmet when they ride a motorcycle, players should be told to wear visors. They aren't growing eyeballs in petri dishes, and all it takes is one stick to end your career. I think that visors, like helmets in the past, should be grandfathered in.