Several others have already replied with posts that basically cover my opinion, but I'll add my 2 cents anyway.
Angeldust quoting 1 Corinthians 5:11-13 writes:
"...12 What business is it of mine to judge those outside the church? Are you not to judge those inside? 13 God will judge those outside..."
I think many churches would do well to take these words to heart. I agree with you Angeldust in that most of the problems I see with this issue occur when churches point the accusatory finger outside of their ranks. Nobody likes to be thumped over their head with the Bible. I believe it is perfectly acceptable for any church to have standards by which their members must adhere to if they wish to remain members. Prohibition of homosexual marriage being one of them. But I also believe that churches could do a better job of acknowledging the fact that homosexual unions of some form will not simply go away just because they believe it is wrong.