If someone doesn't want to party with a-holes like you, that makes them carebearish? He's fine to wait as long as he feels is fit. He doesn't deserve insults flung at him from you for going at his own pace.
And he's right the cm/endgame community is bad. I was going off about how duty finder groups aren't bad from my first dungeon up to lvl 50. How most people were generally nice. But the instant I do cm, the major a-holes come out. First cm run I do people given shit for watching cut scenes, they feel they need to ride the paladin the whole dungeon for not knowing it yet, give him shit for pulling mobs we didn't "need," a healer refusing to heal new people, locking people out of fights, etc. My first Praetorium run wasn't any better either. I had to leave.
Sorry for wanting a nice game experience.