@lakewashington:
The answer to your question is that people have mysteriously placed the first amendment concerning religious beliefs as above all other rights (some of the idiots espousing this say “the first amendment is first because the founders wanted it to be above all others”). There is a local 'defender of the faith" here in NYC (Catholic), whose response to gays being able to marry is that it is bigotry towards Catholics to allow same sex marriage, that it violates their religious beliefs (I guess he hasn’t figured out that the Catholic Church is one of many faith groups, that many faith groups including roughly 60% of Catholics don’t agree with him on same sex marriage, and that the dark ages ended 500 years ago), and he is basically arguing that allowing same sex marriage violates the first amendment (not of course seeing the obvious irony, that banning same sex marriage violates the religious beliefs of those who don’t have a problem with same sex marriage, it is amazing no one tried to argue that in overturning the bans, since banning same sex marriage is based entirely on religious belief).
They don’t see it as Bigotry the way that Bull Connor and racists don’t, the racists claimed segregation was illegal because blacks were inferior, they posed a threat to society if allowed equal access, the religious like your friend throw out all kinds of justifications, that gay couples can’t have kids and marriage is about kids, that allowing same sex marriage destroys marriage, that kids raised by gay parents end up screwed up, and while racists were ‘wrong’ in their beliefs, their beliefs are justified by ‘the facts’ (racists back then gave ‘facts’, too, that they believed, that blacks were less intelligent, that black men wanted to take their women, that black kids would hurt white kids intelligence if they had to go to school together). They basically use religious belief as a justification for their bigotry, so therefore it is okay (in their eyes)
What is really funny is when the opponents are faced with conservative religious folk who are just as convinced that being gay is a sin, that same sex marriage violates the beliefs of their faith,but those people believe that allowing legal same sex marriage is a civil rights issue, that everyone is a sinner and who is to separate sins (like, for example, that we allow divorced people to marry, though divorce is forbidden by Jesus) for legal recognition, and the opponents tell their equally conservative brethren “you aren’t really Christian”.