Most contentious issues--marriage laws, universal healthcare, minimum wage, etc--are explicitly framed and argued (by both sides) with the language of justice. Moral preferences guide law; reason is just post-hoc rationalization.

You might object that "law" is not the same as "contentious issues," but that changes nothing. The emotionally charged political process that drives these debates is the same one that produces legislation. It is almost structurally incapable of producing rational outcomes.