"Well folks, again, it shows how little I know of hockey rules; I mean, if the referee blows his whistle after the puck has already gone over the goal line - why is that not a goal? I don't get it?"

As an on-ice-official, I can answer that question!

First of all, having to make a split-second decision in the fastest game on the planet, is not as easy as it sounds! We don't skate around with our whistles in our mouths(or anywhere else). On any given play, an official must determine whether or not the whistle should be blown. Then they have to put the whistle in their mouth without chipping a tooth(happened to me). Finally blowing the whistle and make the right signal(wave off frantically)!

In this case, the referee has lost sight of the puck and has made the decision to blow his whistle for that reason.