I'm honestly not sure that the social conservatism we associate with religion has all that much to do, in the average case, with religion per se. Fundamentalism is kind of a special case, but most of the time what we see is religious opinion reflecting whatever the standard conservative-leaning package of social beliefs is at that particular place and time. Change the standard and religious opinion follows, perhaps after some lag time -- it's just that religiosity is correlated with a bundle of factors that tend to imply conservatism, and that church events give you a ready-made venue for talking to other conservatives.

For that matter, most of the analysis of fundamentalism I've read treats it as a reaction against secular influences, not an endogenous religious phenomenon. Its phenomenology in the wild seems to be consistent with that -- fundamentalist strains first tend to pop up a decade or two after a culture's exposure to Enlightenment values.