I have this working hypothesis that the unforgivable sins for boomers on the left are sexual.
To be judgmental about the sexual activities of others is unpardonable. This is what makes the Pope such a figure of scorn. The Vatican hangs on to this antiquated notion that we ought not simply do whatever feels good. It can oppose the war in Iraq, advocate a preferential option for the poor and oppose the death penalty, but it will still be seen as a force for reaction.
So the frequently querulous Mike Plaisted can't understand why the media would think it important that the Pope is in the US for the first time in 13 years. They are, he says, sucking up to 71 million Catholics (and millions more who are not Roman Catholic but regard the Bishop of Rome as a unique figure in Christianity). Why cover something that most of the country is intensely interested in ? Better to focus on the obsessions of a handful of secular leftists.
Benedict might do some challenging things like pray for Muslims at Ground Zero, but he also thinks that sex should be limited to marriage so let's ignore him. He can apologize for the church's blindness to clerical abuse, but he won't accept that homosexuality is an appropriate expression of God's gift of sexuality so he is dead to us.
Plaisted is so upset by the fact that the Pope won't countenance abortion that he has actually converted "the putrid Bill Kristol" to Catholicism. Kristol is Jewish, but facts shouldn't sully our stereotypes. The bad guys have to be everything that we think they are.
Mike trots out the old cliche that if men got pregnant, abortion would be a sacrament. For left liberals, abortion is a sacrament and the Pope is a heretic.
Ultimately, the larger problem may be that the Pope represents an alternative source of authority - something outside secular progressivism. I agree that's unsettling. Not all of us want to look.