Unrelated statements. The encounters were designed to be run by more than one player. The amount of work necessary to make the entire game single player accessible would be prohibitive. Also slippery slope logic. Just because I wish not to see thong-frog the shiny purple wonder, doesn't mean I never wish to interact with anyone. Heck I might even have a day I'll interact freely with his incredibly creative and whimsical character.. but I don't want to HAVE to.
MMO's are social as a symptom. By definition they're just games that many people play at the same time, in the same world. I've finished literally thousands of instances without saying a word. I've ground through 2 maps of Eureka without talking to ANY of the mishmash of insanity that is the shout chat. Other people are playing the game in the same world, this in no way means I must give each and every one of them anything above basic human courtesy.