Could be because even one of the worst statistical goaltenders in hockey history gets to keep picking up his fat paycheques.
Dude's having a tough year, I'm sure he'd be much happier to have less money and better stats. If the habs were trying to get to the playoffs, and possibly go deep, this year it would be a pretty serious thing to criticize the GM about. You need a backup goalie if you want to win. This year it's not that bad a move. Primeau stunk, so the draft pick is better. There was a chance Primeau would be good and they'd have an asset.
The money isn't causing the habs any problems, and Primeau has worked hard for it. He may not be a good NHL goalie now, but he got there and he did well at every other level. It's not like he's some terrible human being with no skills or drive, he's probably one of the hundred or so best goaltenders in the world. How many people are top hundred in the world at anything they do?
Look at the Sharks, they have a goalie dominating the AHL who had a couple of great NHL starts. They have him in the AHL so that they can tank.
The habs don't have a lot of alternatives. Primeau has been bad, but Dobes should get AHL time. They can give Hughes a shot, I suppose, and try to find someone else for the Rocket, but why let more goalies lose confidence behind a shaky defence? Let Hughes have some more games and get another RHD or two before throwing more goalies to the wolves. When sitting Savard makes your defence cave in the team has issues.