Rule 603 | Boarding (Note) Boarding is the action where a player pushes, trips or body checks an opponent causing them to go dangerously into the boards. This includes: Accelerating through the check to a player who is in a vulnerable or defenseless position and driving an opponent excessively into the boards with no focus on or intent to play the puck,
Wasn't exactly a vulnerable or defenseless position tho was it? He was already up against the boards. The vulnerable position would be two feet out and being hit in such a way that they could go falling into the boards in a dangerous way that could cause injury. Such as hitting their head or causing a neck injury.
Looks like they both went to play the body the same way. Only one guy was strong enough to do it properly. The rules seem to always favor the weaker player.