You're missing the point of legal marriage. At minimum, it's meant to provide a legal framework for adults who are raising children together so that the children are legally protected under the rubric of a family. Nothing to do (necessarily) with tax or policy incentives.
In order for marriage to be worth anything, it has to be a lifelong contract enforceable in a court of law. If a wife can eject from the marriage at any time, it isn't marriage. If a wife can eject from the marriage at any time _and_ take the house _and_ take the children _and_ reach into her former husband's pocketbook for years on end and possibly for the rest of his life, it isn't just not marriage, it's slavery.
Protesting homosexual marriage after heterosexual marriage has been destroyed is utterly absurd. It boggles my mind to think that anyone is that stupid.
