Cail,
There are/have been several governments who quite clearly haven't given two craps about human happiness (even given the monstrous caveat you admit).
Every government serves to at the very least benefit itself - the quest for power is a quest for personal happiness or pleasure. More altruistic governments serve to benefit certain classes, certain people, etc. But they always serve somebody.
What makes you happy isn't what makes me happy, nor is it what necessarily drives either of us.
I think the burden of proof falls to you here. I say some notions of happiness or pleasure drives human action. If not that, then what?
There are no universals. Anything you can possibly claim as an absolute can be refuted by a single objection.
At the very least, I believe that human emotion crosses cultural, historical, and geographical boundaries in certain fundamental ways. Contrary to what you say, I cannot agree that everything is socially or culturally constructed. The very pervasiveness of certain principles says to me that even culturally-constructed notions are grounded in some sort of "human nature" which I think is a very real and tangible thing. Not something to be merely scoffed at.
You alluded to this earlier, Cail, but I must admit I am surprised to see you taking such a subjectivist stance, being an admittedly religious person. How do you reconcile what you must see as an amoral and shifting world on the one hand, and a faith in God on the other? A converse question could be asked of me; I don't see a belief in God as necessary for propping up human nature. Rather, I see it as a pure human accomplishment.