Blocking shots has nothing to do with the approach to attacking the opposing team bringing the puck out of their defensive zone, which is what the trap is for.
The purpose of the trap is to use the winger on the side the puck is being carried up to squeeze the player carrying the puck out of his zone against the boards, taking the ice away from him, while the center and opposite side winger skate back and towards that side to take away the passing lanes towards the middle. This way the puck carrier has two choices- pass the puck back into his defensive zone for the defenseman to try a pass across to bring it up the other side, or rush to get over the red line and dump the puck deep for the forwards to chase it. If he passes back, everyone skates forward and to the middle to reset the trap. If he goes forward, either he succeeds in dumping the puck or there is a turnover.
Teams have been doing this, or a variation on it, since the Maple Leafs started it in the 1920's. The reason the trap was so effective with the Devils was that if the puck carrier succeeded in dumping the puck in, Brodeur was such a great skater and puckhandler that he was, in effect, an extra defenseman. He would get to the corner, gather the puck and scoot it back out of the zone before the other team's players could get down to it. That's why the Brodeur rule was made. If the NFL was as myopic there would be a Lawrence Taylor rule today banning defensive players from hitting the QB's arm.
Finally, since you clearly find the thought that the Rangers would use a trap as an offensive comment, please read this
article from the New York Times from 1997, where the Rangers were using the trap under Colin Campbell, well before Torts used it.
