I can see where you're coming from but in the end I think kindness and understanding brings out the best in people. I also think that if you use the DF to go into dungeons you accept potentially having a slower run and running into new or less capable players. After all, that's why we get extra rewards, right? If there is a completely new player to the duty, especially a MSQ one, don't be a douche. Show how 'superior' your play is by maximising the situation while adjusting to accomodate and teach the new player in a kind and understanding way. Share your experience, try to make the new player feel comfortable so that later in their playtime they'll be a better AND friendlier player.
Anyway, the fast play you probably refer to as superior isn't being villainized here - efficiency is actually very good. It's the unexceptance from a mentor such as in the OP's situation which is. A mentor's job is literally stated in-game to be, when you click on accept for the mentor status, to accommodate to new players in proper etiquette. This accommodation in the shape of growing efficient and learning takes time, for some more than others. Denying said learning moments by kicking isn't helping at all. Kicking people instead of helping them, and you'll find people generally respond a LOT better to kindness and understanding, will in the long run contribute to a lower skillset of the community for we deny new people proper learning. For those of you wondering (and complaining) why the game continues to get easier: it's because it needs to be... and perhaps now we know why. Take time to properly teach your fellow player if you see them struggle instead of excluding, denying, bad mouthing and avoiding them. Not doing so is the thing that gets villainized here, because this behaviour is detrimental to our community, game and enjoyment in the long run.