Because they honestly believe that the bible condemns homosexuality in homosexuals. The anceint times (in the times that the bible was written) things were much, much different. Not only was there temple prostitution (for both genders) but it was common practice for 'straight' men to use sex with another straight man as a form of punishment, as a way to dominate the other male, as a way to emasculate or harm another man. Post battles where 'rape and pillage' took place is written to be men raping women (due to the sensitivity of the subject) however the reality was that warriors would rape their victims - both male and female as a sign of victory. While women were taken as slaves (wives) the males thus raped were slaughtered in most instances. Those who were taken as slaves were most likely castrated - having all parts 'down yonder' removed. Homosexuality, as practiced by Greeks and Romans and others had specific names, those names were not used in the bible, example Paul/Saul made up a name that was later translated as homosexual, even though he understood and wrote in Greek which had 4 names for homosexuality that would have meant modern homosexuals or gays. He made up a name attempting to distinguish a specific form of homosexuality - many scholars agree that he was pointing at the temple prostitutes. Like modern day street boys, many temple prostitutes (male) were 'straight' they only did it for the money. As such we are talking about straight people doing acts which is unnatural FOR THEM. However through the centuries the writings were interpreted and translated to mean homosexuals and today 'doctrine' specifies all gays, not just straights performing homosexual acts. We get an idea in Romans when we read about God causing straight men and women to lust after one another. There in lies the key straight people doing gay things is the big no-no. Modern Christians have no idea about this separation of meaning, and have been taught (wrongly) that gays are not able to love, that gays are sick, that two homosexuals in love and having gay sex is wrong. When, sadly, it was the abuse of homosexual sex by STRAIGHT people that was and is condemned. The homosexual question is not the only one the modern Christian is wrongly being taught. Things like diet laws and the question of The Law are being improperly taught by the Organized Religions. Like lying, we are not told not to lie, we are told not to bear false witness. Lying (in many instances) is 'ok' such as the white lie where you tell a lie to save someone grief or anguish. Lies (stories) where no one is hurt is ok. Bearing False witness is a whole other thing, it is malicious intent to cause harm. Gossip is not allowed either (same reason) and several other things that Christians do that is strictly forbidden by the most ancient copies we have, in their oldest languages. Anyway, Modern Christians are taught some wrong things about God, Christ and the Bible. The 'gay marriage' thing is one of them.

The way I have always heard it debated was that it isn't necessarily the disapproval of a relationship that isn't a man and a woman but the word 'marriage' itself. Christians say its their word which by their definition means a man and a women. The argument is that a civil union gives the same legal rights to gays as does a traditional marriage but the gay community say they want the word because it sounds better. Of course on top of it there is the anti-gay Christians too.

Most Christians believe that gays have chosen their lifestyle. That means that they could change. Others agree that some people have a predisposition to gayness somewhat comparable to way that some people are predisposed to alcoholism. They believe that such people should not have sex if they wish to remain serious Christians. I think it's unrealistic, but that's what they believe. The Bible does have some anti-gay passages, so that's where they get this attitude.

The fight really started 100 years ago when the state governments decided to regulate marriage. This was done to prevent interracial marriage and in the case of Mormons polygamy. Up to that point the Christians are right marriage WAS a spiritual union defined by the church. When the Gov. decided to get involved it redefined marriage into a secular institution. Going so far as licensing pastors and civil authorities who perform marriages. Gay civil unions are not the same as heterosexual unions in so far as they don’t offer the same benefits, legal status or recognition. The most glaring example of this is DOMA ( Defense Of Marriage Act) witch is used not only to deny gay people tax benefits but also passports, social security… Of course fundamentalist churches fight against gay civil unions too. To say this debate is all about a word {marriage} is not accurate. It’s about two words. {self determination} Can a church that has already determined that I am unfit to worship their god then reach out and redefine citizenship? And if allowed to define it for me who will be next?