I agree it's bad news. It may be that he will be against us more than 10% of the time. But I am an incurable optimist. I still expect him to be between Rehnquist (90% conservative) and Scalia (98%). (I have been watching the Court since the Rehnquist/Scalia nominations in '86.) Roberts was helping the left on that case, even though he knew himself that, if push came to shove, he would vote the other way. Am I convincing?
It's quite possible. Logically, it doesn't matter if Roberts sympathizes with the gay-rights agenda or not.
If he's willing to keep the courts from advancing it, that's fine with me. However, the litigation he helped with was aimed at precisely that. If Roberts thought these clients were seeking an illegitimate ruling, he should have stayed out of the case. It's not like he was some vulnerable young kid just out of law school. Roberts could have taken a stand against this abuse of the process, and he chose not to. So either he is insufficiently principled, or he actually believed in the merits of the gays' lawsuit, which were zero. Distressing.