> A world in which everybody is happy and content with who they are and the circumstances they live in, how is that dystopian?
Because being happy and content is by far not all what makes life worth living, and these people are stuck in eternal mental infancy. And they don't get a choice, either: they are conditioned to despise natural birth, not sleeping around, and deep affection -- and the caste system is proper for insects maybe, but not fully developed human beings. It is not what they eventually happened to agree on, it was engineered that way, they were born into it without even the ability to see what has been done to them, and all of this calculated. They are instant gratification junkies in an endless loop of mental stagnation, what's not to hate?
> but never really justified why they'd be necessary. All of them (and the 'orgy-porgies') were, I felt, added to be able to make the argument that the society he was portraying was morally wrong.
Do you think Huxley is making the argument that "being happy and content is bad", and the rest is just filler? If so, read his this one:
http://en.wikipedia.org/wiki/Island_%28Huxley_novel%29
Clearly, he's not against being happy and content. But it has to be real and come from within, not just from being deprived of the ability to grasp injustice or reasons to be sad, or reasons to love (which implies the possibility and eventual reality of loss, too).
If I injected you with drugs that made you a mindless, but very happy and healthy zombie, and hooked you up to IV everything-you-need -- "you" (there would not be much left of the former you) would love it, but how would your friends react? Badly. Does this then mean they are against happiness? Of course not.