Gaining exp even if dng is unsynched

[Atoli]

I really like that people are all for making the MSQ continue to be mandatory then say stuff like, "don't actually run the MSQ dungeons to level, level with some side content instead".

That's because people realize there is a difference between "run dungeon X once to continue the story" and "run this dungeon 20 times to level up"
Personally, I like leveling in dungeons, so I don't mind the DPS queue times. But it's not like anyone can get stuck that way - since there are a myriad of other ways to level up:
from the massive exp gain from the MSQ quests to PotD to FATEs to hundreds upon hundreds of sidequests, beasttribes, the weekly agenda and so on.
Continuing the MSQ does not mean one must only solely level through the MSQ, and it was never meant to be that way in the first place, even at ARR release, so I don't see where your complaint is coming from.