No one is forcing you to do fates, I know couple of people who don't like the fates and like to do quests for tokens to sell for gil, regardless, I know fates exp is tempting and I don't know if that's intended or if its just broken, but no, no one is forcing you to do them, you are the one forcing your self to do them, DF has a really nice amount of exp per run but still has its issues, not to mention lack of tanks, but you can always hit DF while you Quest/do fates, I do that always, I enjoy Dungeons at any given level, helps me learn my class/job and test things before I hit the end game.