DPS specs often get blamed the most for not knowing what is going on. It should be your business to understand the mechanics of the fights. You’re a member of a team, not a follower who can always rely on someone else to tell them what to do. Which are the spells that need to be interrupted? Which are the void zones that you absolutely must get out of? Which are the adds that must be burned down (and conversely, when should you ignore the adds and focus on the boss instead)? If you aren’t sure, then ask. [emph mine]
No, you shouldn't have to ask. Nor should DPS stay in the LK theme of button spamming. Instead, the game should teach you each instance fight.
Essentially, what Blizzard's saying here is if you're not in a hardcore, first-run guild that's going to blast through the instances first, you must learn from what those guys have said. If you're part of the second wave, it's your responsibility to figure out the instances from outside of the game. You must read Thott/WoWhead. You must have someone in your guild that has already run the instance. You can't do this on your own, Nemo. You just can't!
The attitude's a cop out. If [PU]group members are going to continue to expect you to get it right the first time or they'll drop -- an attitude, it should be pointed out, this blog post by Blizzard reinforces -- then the game must include clues, preferably from the content of quest lines that teaches you how to handle an instance. There must be in-game methods to learn the lore. As much as gaming is an industry of metalepsis, how to run an instance should be taught in-game.
There's no RP reason not to think that the weaknesses and powers of the instances aren't known by some NPCs, and there's no reason not to make quests, accessible in solo PvE, that prepare us for boss battles in instances. I think I've mentioned that here before. I know I've thought it. It's not rocket science. The move's obvious. Lore in game, please.