As an agnostic with no "horse in this race", I have to say that I have no clue why Spong and people of similar beliefs can't just leave their Church and found their own thing, when it's pretty clear they don't believe in even its most basic tenets. I mean, it's one thing when you're committed to a Church but feel it's misguided on some specific points, but what's the point of still calling yourself Anglican, Presbyterian or whatnot, when you just don't fit the definition in any way?
Probably because everyone has the attitude of "I'm the one who's right, so they can leave, not me."
I mean, I'd love it if all the minority of Catholics who are anti-gay and anti-abortion rights would leave for some other church, and then the remainder could merge with the Episcopals (minus these weirdo South Cucklinians) into an "all liberal, all the time" One True Church. But that's not happening -- that minority thinks think we should be the ones to leave.
Christianity is does not revolve around 'Murica.