While it doesn't look good for Backlund to be taking a swipe at Skinner, it's egregious for Skinner to fall like he's been shot. Yes, it was to an unpadded area, but it was a one-handed swipe almost like "Hey, I'm behind you watch out." as opposed to something malicious. Backlund could have swung for the fences if he wanted to hurt Skinner, or simply have run him over; risking a penalty but causing much more collateral damage. Nothing about this play screams malicious though Backlund should have gotten a penalty on the play, but not to have his head taken off like the Oilers wanted.
Plays like these in hockey are a dime a dozen, and some teams like Calgary get away with it and sometimes they don't. It's the nature of the game, and you have to play the hand you're dealt with.