I actually agree with your proposal to get the state out of recognizing marriage (from what I suspect is a diametrically opposed political position). But you need to acknowledge that this would mean massive changes in many, many aspects of government policy. In the United States, state recognition of marriage is built into our tax structure, immigration policy, all aspects of social security, the regulation of trusts and estates, health care...the list is pretty much endless. Unless and until we change all of those policies, the failure to recognize same-sex marriages is discriminatory.