I didn't want to derail this thread, but I also wanted to continue the discussion. Is Pathfinder a PvP game?
The idea (hopefully without straw-manning) is that the GM makes appropriate encounters, then does everything they can within those encounters to win.
I'd say it's pretty clearly not PvP. In a PvP game, players can ONLY win by beating the other players. A TPK, while it might be fun for some GMs, seems to me to be a loss for everyone involved.
As a side note, enemies in Pathfinder are non-player characters, and the GM isn't really playing NPCs the way players are playing PCs. The only players are the PC's, so unless they are fighting it cannot be player vs. player. That might be semantics, but I think the difference between PCs and NPCs is important.