I have been looking around this thread, it is very interesting. I am not a Roman Catholic so I am not sure I can comment on the specifics of the Roman Catholic response to gay marriage.
I have been thinking about this a lot of late and I know the subject of gay marriage is something other denominations are grappling with too.
I went to an Anglican (Church of England) Church for many years and of late we have attended a free church.
If you wish to read about other denominations response to this subject, this is quite interesting:
www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10860110
Or to listen to Steve Chalke:
I could not find the actual 'talk' except on Adrian Warnock website:
www.patheos.com/blogs/adrianwarnock/2013/01/steve-chalke-and-others-on-homosexuality-and-gay-marriage/
And www.acceptingevangelicals.org/
For me features of the 'argument' are (as well as some people thinking they are right and what they think should apply to all) that perhaps for the majority this is something they feel really compelled to believe in. So not exactly a choice for them, if you see what I mean. It does not mean the rest of society has to agree but I am saying they are not necessarily being ?awkward? in thinking this! Does this make sense?
Another major factor is a fear that if the laws are changed than Christians will be compelled to do things they don't want to do, such as perform gay weddings in their churches. I fee (just my humble opinion) that churches should be allowed to perform or not perform gay weddings in their churches according to what that particular church believes. There are a number of gay bed and breakfasts in the UK. Whether all of these are exclusively for gay couples or not, I don't know. But certainly some will want to receive gay customers as opposed to others. I think they should have the right to have gay people staying only. By the same token if any others wish to only have straight people in their bed and breakfasts then I think that is fine too. Some people have been prosecuted for not allowing gay couples in their bed and breakfast. So again by the same token I think churches should be able to choose whether they will marry gay couples or not. I do genuinely think that this fear of being prosecuted/persecuted because of this issue is what is partly driving many churches to be so critical. It does seem that individual Christians have a variety of beliefs, and churches do too, but that fear is a factor.
Just wanted to add my thoughts. Hope you do not mind.