I, on the other hand, much prefer being able to play an MMO solo and grouping with people when I decide to be social. Locking content behind grouping is just plain annoying. As with all games, I'm there to explore the world and the story and the less I have other humans involved in that, the better in most cases.

Then why play something centered around multiplayer content when there are multitudes more single player games focused around that exact play style?

I’m there to explore the world and the story

And avoid 90% of the content and make MMOs feel even lonelier than they already do

Doesn’t sound like the original commenter has that problem!