Honestly? It seems pretty clear that Dumbledork looks at the game slightly differently from the rest of us, due to his completely singular experience with playing the game. This is shown with his mentioning of Booty Bay and Xroads as being areas under attack, as well as his disinterest in doing dungeons.
Dumbledork... Its quite often that people wipe in dungeons. Generally, if either the tank or the healer dies, thats whats going to happen. It doesnt mean a group is fail. If you have a rogue or a mage who gets bored with sitting around and starts making pulls on his own, thats not 'leroying'. Unless you're ridiculously undergeared, a party can generally keep on pulling nonstop. Assuming you're playing on a hunter or warlock (the only classes I've seen you mention), it's even easier, as you can always just trap or fear a mob running at you.
Many people may disagree with me here, but WoW is very much a game of skill. There is a HUGE difference between people who suck at the game, people who are ok at the game, and people who are good at the game. Its excrutiatingly easier to be a decent hunter. Especially if you're BM, spamming Steady Shot all day doesn't take skill. But even that minor attention to remembering to set up a trap before a pull in front of you, so that your CD is up by the time the mob breaks, is a lot harder then most hunters can manage.
The point here is that you may be misunderstanding what exactly is going on in dungeons, from your extremely limited experience with them. Because of this, you mistake something for failure where it is not. Unless you decide that Arena is where you want to be at 80, you ARE going to need to start trusting people in instances. For me personally, raiding is the most fun thing in the game. Nothing else even comes close. You are missing out on quite a bit by passing over instancing all together from a few 'bad' experiences.