It's hilarious how much non-goalies cry about this.
How about this, when your number 1 goes out to play the puck and someone like Martin decides to truck him, he gets done in for 4-6 and your season is effectively done....but at least you proved your point or something.
Also most goalies are 6'1 230lbs+ on ice, so if you wanted them to be fair game, players would often be on the receiving end and likely deal with injuries as well.
So in short, people want to see more injuries and more goalie injuries, GREAT IDEA, someone forward this thread to the NHL, I'm sure they'll get right on that. At least a few mean goalies that have hit players might get it back, THAT'LL SHOW EM!!!