First of all, I want to say that agree with him 100%. But the point I want to make here is another one.
We've seen this script before. Several times, in fact, over the last couple of years.
A graduate of Yeshivat Chovevei Torah publicly declares support for something that Orthodoxy traditionally rejects. Orthodox Jewish social media then spends weeks obsessing over and over again about whether he can be called Orthodox or not. And in all the debate, virtually no ink is spilled on the actual issues he raised. And that's a shame.
For the record, I support gay marriage, 100%. As a human being. As the right thing to do from my personal moral perspective. My religiosity is irrelevant to this issue. And whatever denominational label my coreligionists want to slap on me as a result is truly irrelevant to my identity as a Jew.