His argument is that same-sex marriage does not upset the Blue model, but disrupts the Red model. Hence it is too simplistic to label opposition as hatred. It's more that people are struggling with models that no longer fit circumstances. It's a generous and open minded response to the people who attack him, as a same-sex marriage advocate. He acknowledges their legitimacy but without capitulating.
It is not that I think same-sex marriage opponents are right...I would merely point out a kind of integrity in their position... The deeper arguments here are over what constitutes family normalcy, and how we structure the transition to adulthood, and who is entitled to set up a family at a time when many American families are under all too much stress... Gay marriage opponents are wrong, I think, to see gay marriage as the problem and its prevention as a solution. But they are not wrong to believe that... the new rules are not a perfect or complete or sometimes even adequate substitute for the old. And so I would hate to lose touch with the traditionalist ethic along the way to whatever is coming next.
It's just a great example of how to engage with political opponents. It's reasoned, open, non-aggressive. I don't think it will convince traditionalists, but it makes relations with them more civilised.