Imagine a guy taking a month of holiday to do a road trip from New York to San Francisco. He sees a lot of America, has a lot of fun, and relaxes. A successful holiday. The fact that he could have gotten from NY to SF much faster and more efficient by taking a plane is irrelevant. Getting from A to B was not the purpose of the trip. Calling him a "n00b", or a "moron & slacker" for not having choosing the fastest route is utterly ridiculous.
The same is true for MMORPGs. Sure, some people have fun pursueing goals, and some like to reach those goals as fast as possible. But that does not make them better players than somebody who spends his time role-playing or exploring. There is no win-condition in a MMORPG; getting from level 1 to 80 with all best-in-slot items in the most efficient way is irrelevant. That is especially true for World of Warcraft, because Blizzard is notoriously slow in releasing expansions. Getting to the end of an expansion faster only means you are blocked for longer without anything left to do. And it doesn't exactly make the fast players more sympathetic that so many of them appear to use that time with nothing to do for berating other players for taking it slow.
One could even argue that the most efficient players are the least good, because by definition there is only one most efficient path and taking it is the least original way of playing a MMORPG. There is only a handful of players actively engaged in figuring out the most efficient path, the large majority of players just copies and pastes the findings of the theorycrafters. How many players rush through content in the fastest possible way, following somebody else's description of a most efficient path? That is certainly one possible way to play a MMORPG, but I see no justification whatsoever to claims that this would be the "best" way.