I wonder - could there be some consideration other than how many games the player is missing, for example how much it is costing them in salary? Though Lapierre sits out four games, his suspension only costs him about $33.5K. Ovechkin sits out 2, and his suspension costs him about $232.5K. There is also the fact that Ovechkin sitting out is also punishing his team much more than Lapierre's suspension is punishing his (and I know that the team bears some responsibility for their player, but this isn't a case where a coach told OV to go out and give Campbell a tap... or a push ... or whatever). I just mean to suggest that there are other factors that play into it other than the incident itself, and the history of the player involved.
I would like to see Ovechkin suspended for longer (well, except for the little voice in my head screaming, "But he's in your pool!") - but that's the case with Lapierre too. I'm just not convinced that these punishments are inconsistent with one another.
As for whether Ovechkin is dirty, I don't think he is. I think of someone who is dirty as intending to hurt people, and I don't think that's Ovechkin's aim. He seems reckless as hell to me, and he really owes it to his fellow players to be safer out on the ice (particularly given his strength), but to me that's not dirty. That's stupid and selfish. Neither is good, but there is a distinction.
I'm hoping that Ovechkin feels bad about this. That he really didn't mean the consequences of his shove, and told Campbell as much, and was convincingly. I hope that he smartens up on the ice a bit - he can still be exciting and powerful out there, but without this stupidity. I guess time will tell.