You're responsible for where you shoot the puck, so Watson takes blame and responsibility for that.
Having said that...players on the losing team shoot the puck towards the net at the end of the game, in frustration or otherwise, all the time in this game, especially if it looks like there isn't much in the way. If he lost sight of Lauzon being there, again, he takes responsibility for that, it's not an excuse to lose sight of somebody. But I hardly imagine he was doing that in an intentionally dirty manner, so spare the pearl clutching. What he tried to do happens at the end of NHL games every night.