It also goes against the philosophy that they use in terms of things like the unskippable cutscenes in the MSQ Roulette, which is for newer players to be able to "Have the experience as intended" which having other players skip the cutscenes and run forward and wipe out the entire dungeon before the first cutscene finishes doesn't adhere to.
Which also overlooks the point where due to level sync being kind of mediocre for actually bringing players down to a reasonable level, it means that new players still don't get an "Intended experience" because sync'd players just decimate everything anyway (Heck, all the "Bosses" in Praetorium/Castrum Meridianum die in less than 30 seconds. I don't even know if they even have mechanics because I've never seen them)
This can also extend into other duties, where new players can find themselves just running along trying to keep up with a party of sync's that are just zooming ahead nuking down everything before the newbie can do anything (I've seen it happen in some of the lower level duties). I've also seen some final bosses be killed before a newbie has finished watching its intro cutscene.
So, while maybe it's intentional to aid with allowing Duty grinding for high level players, whom just want quick runs. It goes against their premise for allowing new players to have the full experience of the duty.