You can't just brush over that fact. The force of the hit/shove is the main discussion here. Letting up and not following through with full force shows there is no intent to injure or break the rules. It's a natural instinct for the trailing player to put up his arms to brace for contact in that position. It's a very common play and you can't eliminate it from the game.
All you can eliminate is the urge for the trailing player to follow through with a full hit/shove which can cause injury. Carcillo clearly didn't follow through with a forceful hit. Ovechkin did.
One resulted in an injury and a penalty on the ice. The other resulted in neither.
-The other thing I didn't do is read posts (I still haven't -not that much time to do that).
Ok, here's the thing - it is a valid point about pushing; however here is the thing - the high sticking rule was changed to eliminate intent as an issue for giving out penalties -the onus was on the player to keep control of their stick -and if it came up and clipped someone -no matter what the reason - the player got a penalty - if there was blood, generally it was a major instead of a minor.
What I'm getting at is that maybe the logic behind this is similar (for the NHL head office), that the players need to be responsible for their own positioning.
It was a dangerous play, anything that happens that close to the boards is dangerous -particularly when you got another guy piled on top of you - you the initial slidee (the one going to impact the boards first), have limited control over what you can do about protecting yourself (in some cases nothing).
I still think this is largely an issue behind the scenes between the head office officiating administration guys and their on-ice officials.
---
If you look at how the league started calling what used to be legitimate stick checking as "hooking" a few years ago - they are being consistent at least ... although, I do get that it does make things different on the ice.