My friends are really bugging me about this?!?

So me and my two friends have hit sort of a rough spot. On friday though it got worse. We were talking and some how the prospect of religion and political views came up. I have very different views about these things. I am a christian and they are not but I am not ultra religious. We then started talking about gay marriage though I have no idea how it came up. I said that I do not believe in gay marriage because of what the bible says but I have nothing against people who are gay and would be for it if it did not say so. Then one of them went off into saying how stupid it was and she actually said it was stupid. I got really offended especially when she started talking about how the bible was hypocritical when she has never even been to church or read the bible. My other friend just sort of nodded her head when my friend spoke and now I am sort of mad at them. I understand that people are entitled to there opinions but I feel like they have no right to judge it that harshly when they have not had any experinces reading the bible or anything else and then tell me that I am pretty much stupid for believeing it. and that is exactly how I felt for the rest of the day, stupid, for even letting it be brought up when I know they do not view things the same way I do. So does anybody have any ideas of what I should do? If I told them they had no right to judge it when they do not know it they both would go off in a rant about how this is america and they can judge things if they want to. I have other friends that I could hang out with but I just don't want to go into that awkward point of hanging out with other people.