Okay, I'm a Cradle Catholic and probably what most people term as "Cafeteria Catholic" too. I tend to make people mad that way. Let me explain why I'm a "Cafeteria Catholic."
I believe that government and religion are two different entities. If the government allows prayer in school, the government has to allow all forms of prayer in school which would cause all kinds of discrimination against people. (I've personally had to deal with this, but that is another blog.) Therefore the government cannot allow prayer in school to avoid discrimination. This is something that the Church doesn't like (discrimination). We don't like racism, ethnocentrism, etc. But the Church wants prayer in school. So one is left with a choice. Which is more moral: prayer in school or discrimination against other faiths? Anyway I'm just using this as an example but I will talk about prayer in school later.
The same principal I feel is applied to gay marriage. The Church says gay marriage is wrong. As an institution the Church doesn't perform gay marriages. No problem with that. If the Church says that it is against God, then I believe that it's against God.
But here's the rub. If the Church feels that only Catholic marriages are valid, then they are also invalidating marriages of other faiths and those who are atheist. The Church doesn't perform these marriages. Other institutions including the government do. The government is then forced not to discriminate because in the constitution it allows for religious freedom. Therefore the government must validate marriages of all faiths (or lack of faith).
The government can't discriminate marriage based on religion; it also can't discriminate based on gender, ethnicity, race, or age (well it sets limits but that is also debatable in some societies even in the US). Governments are supposed to protect all people. In Canada, they have laws set up to protect long term relationships whether it is unmarried cousins who live together or gay couples. This gives those closest to an ill person the right to decide medical care and so on. The United States doesn't recognize such relationships which is why many gay couples want the right to marry.
This leaves the government two choices to avoid discrimination: set-up a system that recognizes long term relationships or have gay marriage legalized.
Now where does that leave the Church? Well the Church is protesting. They feel that marriage is between a man and a woman only. Fine; I totally agree with that for the Catholic Church. This is what makes me a "Cafeteria Catholic." I believe that the Church should not have gay marriage but I believe that that the government should have gay marriage. The Church is protesting marriages within a secular institution, which I believe isn't right. The Church should not be allowed to dictate what another entity does (unless it involves something deadly).
I'm a musician and many of my friends are gay. I've never known any of them to be evil. In fact many of them are religious. Even the Church accepts gay people (just doesn't want them to engage in the acts). So I think gay marriage is totally different than say war or abortion. Gay people don't hurt other people. Gay people aren't hurting themselves. We are all sinners so I don't think it's right for me to look down upon a gay person.
In my mind the Catholic church is counting all types of marriage as being invalid when protesting gay marriage (because not all gay people are Catholic). But if you ask a priest if a Jewish person is sinful because they didn't have a Catholic wedding, the priest would probably look at you a little funny. Ask the same question about a gay wedding and that depends on the priest (I know a few who also agree with me about separate institutions).
It comes down to this moral dilemma: do we want to be more ecumenical as a faith or do we want to invalidate all marriages outside of Catholic ones. For most "faithful" Catholics they choose to protest against gay marriage (and also seem to unknowingly promote invalidity of other marriages). For us "Cafeteria Catholics" we pick the other route, we want ecumenism. We don't want to discriminate against others; we want our religious freedom.
It's not an easy answer for anyone. But I think those who are "faithful" should start looking at the beam in their eye before they start calling those more ecumenical among us "Cafeteria Catholics."