It's debatable that two people getting married is the same as two other people getting married? It's only debatable if you think that a black marrying a white is different than two white people marrying each other.
The act we're discussing here, is marriage. Two people getting married. If you make constitutional distinctions between same sex marriage and heterosexual marriage, the government is telling people that it feels gay marriage is different. Since the only component of gay marriage that is different from heterosexual marriage is the participants of said marriage, it implies that homosexuals are different enough in such a way that, constitutionally speaking, they do not deserve to have their marriage validated and recognized to the same degree that a heterosexual marriage does.
You may not have said anything to the contrary, but given how quick you are to discuss and go on about political issues you don't agree with, including political discussions not even involving your state, in addition to concerns about compromising the freedoms and rights of individuals, I'm rather surprised you haven't actively spoken out against the Texas amendment. Although you have danced around the issue quite well.