Well, in my opinion, McDonagh did contribute to this hit by getting in Andrew Ference's way. Shanahan describes this as a textbook example of boarding, but to me, the textbook boarding has been when someone lines a vulnerable opponent up, then strikes when the opponent CANNOT defend himself. Not when an opponent obstructs your path to the puck, then places his legs in such an awkward wide stance that he has decided not to defend himself.
Ference, a relatively clean player, now has a black mark on his record. He got suspended the same number of games as Ovechkin did for this hit:
So Ovechkin launches himself, hits an opponent in the head, and has a history of suspensions and fines. Ference boards McDonagh, doesn't hit him in the head, and has no history of dirty play. And they're suspended the same number of games?
Shanahan admits that Ference shows no malicious intent in the hit. It was perhaps reckless. In which case, a fine or one game suspension is sufficient, I think. Then if Ference develops a habit of reckless hits, the suspensions can increase.
Ference is a 12 year veteran with a clean record and he gets suspended 3 games because McDonagh braced himself awkwardly and tried to block Ference from the puck. Seems a bit harsh.