I agree.
Forget about intent to seriously injure for a minute (I don't believe the intent was to seriously injure - if so he would have swung at his head).
No one should ever get away with swinging a hockey stick like that.
Is what Osgood did wrong and is it punishable? Maybe, I don't really know but that does not excuse swinging a stick like a bat.
Oh yeah, and as if that hurt Osgood.