I wouldn't say it's a trait unique to high level players. Any manner of players can be rude and uncommunicative in a run. But there are a fair number of endgame players who have several roulettes to get through, not just the one dungeon, which can explain but not excuse their poor attitude.
I tend to go with what the whole group wants. If someone asks for a full clear I'll ask the other two people if they're okay with that. If they are, we'll explore the whole map for you.
