These guys might be able to explain conservatives' behavior:
Moral Foundations Theory proposes that five innate psychological systems form the foundation of “intuitive ethics.” Each culture constructs its particular morality as a set of virtues, values, and ideas based on or related to these five foundations (as well as to many other non-moral aspects of the evolved mind). The current American culture war can be seen as arising from the fact that liberals try to create a morality relying almost exclusively on the Harm/Care and Fairness/Reciprocity foundations; conservatives, especially religious conservatives, use all five foundations, including Ingroup/Loyalty, Authority/Respect, and Purity/Sanctity. In every sample we have examined (including samples in the US, UK and Western Europe), political conservatism correlates negatively with endorsement of the Harm and Fairness foundations, and positively with endorsement of the Ingroup, Authority, and Purity foundations.
Maybe I'm just a hopeless liberal atheist, but Harm/Care and Fairness/Reciprocity appear to be legitimate moral values while Authority/Respect and Purity/Sanctity are just a bunch of nonsense. Ingroup/Loyalty is good in some circumstances, but is probably also at the root of most evil that goes on in the world.
What good is Authority/Respect? Is "I was only following orders" really a moral justification? Following authority is moral when the authority figure commands moral action and immoral otherwise.
Do I even need to point out how dangerous Ingroup/Loyalty is? It's nice to watch out for your siblings and countrymen, but there's nothing moral about, e.g., going to war for your side when your side is in the wrong.
As for Purity/Sanctity, how is that a moral issue? Oh, she had premarital sex, therefore she's immoral? She's on her period, so it's immoral for her husband to touch her?
Obviously, this is an over-generalization, but this confirms my intuition about the American culture wars. One side cares more about people; the other about abstractions like Authority, Loyalty, and Purity. In my book, any time you support a policy that leads to more deaths, more harm, or more unfairness for some intangible reason, you're probably doing the wrong thing.
This divide is quite clear even within religion. Conservative religious groups worry about following rules (authority) and being holy (purity) while the liberal ones focus on charity (care) and social justice (fairness.)