I can't call it the dumbest call in the word, but it's a frustrating one as a lot of these have tended to be automatic penalties, you slash a guys stick out of his hands or lift a stick too aggressively and through the stick through the air....it's a penalty, but how do you assess whether it should be, meaning, the other player is responsible for holding on to his stick as well. Some would say, well, you did slash the stick, that isn't allowed right? The answer to that is yes, that's true, technically that is slashing, but obviously you can't call every little thing like that, there would be 25 penalties every shift.
I think this one, if the ref is simply watching those 2 players the whole way he would have probably assessed that he didn't slash the stick hard enough for it to be considered a penalty, but did he see it out of the side of his head? I can see where the call is made.