Usually in lower content and 4-man dungeons, if a newbie is in a cutscene I'll tend to wait (on tank). But if I'm on healer or dps and the tank doesn't bother to wait, I don't really see an issue with it. And higher level content such as raids, it really, really doesn't matter. Dungeons in SB and ShB also have mostly done away with the super long cutscenes before final boss stuff, as well. Not like people get locked out of boss rooms now, either.

So typically if someone pulls, I'll be running in with them. There is absolutely no excuse for someone refusing to do their job or join their fellow party members in the room, simply because one person is still in a cutscene and you personally find it rude to go in or worry about a first time experience being ruined. Actively attempting to sabotage a fight by not joining in on a tank or healer is especially egregious and toxic.

Not that the passive aggression in this community surprises me much anymore, but still.