It looks bad in slow motion (not all that bat, relative to other), but I think he thought that Stepan would turn and skate the puck up, not come to a stop at the boards. Didn't seem like he intended to go for the head.
I'm not a fan of the Bruins unless they're playing the Rangers or Devils, but I think that 5 and a game would have been sufficient.
I don't think that's what he thought - I think he was just finishing his check and came up a little high.
But I agree, definitely not all that bad relative to others that go unpenalized, let alone unsuspended. Check out the hit by Tkachuk that led to a fight (also check out different angle starting at 0:44):
How in the hell is that not both charging and
boarding?? Not even a penalty called. That had a lot more potential to do damage than Lauzon's hit. Also, Stepan is a bit of a drama queen. I hate the Bruins with every fiber of my being, but that hit was pretty close to nothing and should have just gotten a minor or a major with no suspension, IMO.