I've only done a little bit of reading about the prop 8 decision, but the impression I'm getting is that the court was handed a nearly untenable situation, and they decided to make it even more untenable, because the underlying situation is fundamentally unstable and needs to be dealt with. Like a game of Nomic that's just about over.

Within that framework, I think they said "everyone should have the same rights to marry" and "the current Californian constitution and ability to modify same is utterly stuffed".