Thing is, if you’ve coached or played you know it’s a good strategy.
If one man stays high when the other team pulls the goalie, it forces the opponent to not fully commit to manning the point. But even if they do, and the puck comes out, it’s an easy EN goal. Game over.
The popular fan idea that all the players on the team in the lead are supposed to drop into a d-zone shell is a recipe for allowing prolonged pressure at the very least (and icings). Most teams with the extra skater actually prefer it.