I'm all for people to be allowed to watch their cutscenes on the first run of a dungeon, but if the rest of the group outgear it so much that they can defeat the bosses with ease without waiting on the new players, then I think it's a bit much to expect them to wait through every cutscene every time they're with a new player. Especially in Praetorium and Castrum Meridianum, there are a ton of cutscenes and the bosses are trivial as hell nowadays.

As long as they aren't giving you flak for watching cutscenes, they're being considerate enough. Waiting until you're done watching cutscenes would make the dungeon take roughly twice as long.