So let's step into this then and why it's a flawed argument on -either- side...
You can not compare a single player game to an MMO, in no instance is this valid. Anyone can play a single player game for as long or short as they want in whatever free time that they have. It is not beholden to any one else, either from a skill or availability standpoint. The expectation out of an MMO and the very specific demands it places on time are simply unmanageable for some people on the hardest content.
Sometimes it's not a matter of want. Sometimes it's a matter of can't, simply from a design perspective. And the point you are arguing against from the post you quoted was someone simply saying, "Don't lock the kinds of things I currently can get away behind something that will keep me from getting it."
This is going back to people thinking that end game is only for hardcore raiders. No one was complaining that we can't get Savage gear. We know that we aren't to that point, and while we might not be totally satisfied with the difficulty or the inherent content in what we do have. What people are saying is, "Don't take away way little satisfaction we -do- have just because you think it takes away from -your- experience", which... by the way... it doesn't.