There's really no comparison between Weber purposefully slamming Z's head into the glass --and then laughing and joking about it with team mates later, for the cameras to catch -- and other less intentional injuries inflicted during the heat of a game, as with the head shot to Datsyuk. Much as I hate that Pasha is injured, I don't believe Cowen's act was as intentional. He might be pleased after the fact that he got away with it, but I am not sure he's smart enough to plan that action out as a way to remove Datsyuk from the ice.
Weber didn't 'deserve' a puck to the face, of course, as retribution for his low-class action toward our Captain. It deserved punishment from the league, needless to say, and didn't speak well of Weber's character.
Does Shanahan skew his judgments, or lack thereof, when a Wing is the victim? Why, yes, it does appear that way. Disappointing.