You keep ignoring that, depending on how far back you step, there is precedence for gay marriage already present in our legal system. We both have the precedent of marriage at all and the call for equal treatment under the law. Refusing gay marriage already violates both of those, we don't need yet another amendment for it.Because there was precedence in other laws. Using the discrimination tactic worked because of that. And they could not alter those things, originally without an amendment.
But you go right on believing whatever you want. More and more states are discovering that gay marriage should already be legal and are declaring it so without any amendment process.