I'm not assuming anything, except that we have different play styles and generally different goals when playing that affect our ability to enjoy the game together. Posting advice that basically says "then just don't play with other people" doesn't address the underlying lack of communication or help the original poster deal with his frustration.
I don't know why the last post was addressed to me, since I wasn't making any negative assumptions about other players just pointing out my perceptions of Turbine's game design and that there are other ways to play the game that don't involve farming for experience points and loot, or completing any objective that is quantified within the mechanics of the game.
If you operate under the assumption that someone has the same goals, when really they don't, it's easy to ignore the fact that your behavior is actually causing problems for them. This would be true if you posted looking for a fast run elite BB and a a role-player joined or someone wanted to kill every mob in a walk-up and you rushed ahead to the entrance. Or, as I've had happen, you post for normal and another player opens the quest on elite. Assuming that everyone who plays the game plays it your way, that there is a normal way to play, that others need to adjust to it or be stuck soloing content isn't fun for anyone on the receiving end of that assumption. It's not one type of player's fault. Everyone should be explicit about their goals in the LFM to avoid these problems. Clearly there are enough of both types of players that with a little understanding we could all find groups that have the same objectives.