I can understand the rationale. To simplify it, it's like when I was younger... it made no sense to make my bed up. It is only going to get messy again! Or like when my mother said, "Don't read in the dark." Me: "But I can see Mom!" Dad: "Don't sit to close the the television." Me: "Why?"<quoted text>
It is ridiculous and without any rationale *whatsoever* that two people of the same gender who naturally love each other should not have a loving relationship together. In fact, it is extremely callous and cruel to deny a gay person a partner simply because of gender.
Christians hypocritically turn a blind eye to the outdated immorality of the Bible when it comes to slavery, sexism, and racism, but they still cling to homosexuality. I've got news for you, just as with those other issues you had to side with social progress over your Bronze age book, you are going to have to do the same with homosexuality too. Is it really worth sacrificing your religion over an irrational bigotry? You didn't think so for slavery, sexism, and racism...
Those things didn't make any sense to me whatsover at the time until I grew up and understood why. But concerning male and male/female and female intimate partnerships... to make a long story short it is simply not the way God had intended. Heck, not even hetero- relationships outside of marriage is not what God intened so there is no bias there. The simple answer is that it is sin. I understand that you don't believe that and that is your right just as I believe it as an absolute truth and that is my right. Right?
But speaking to slavery... there were all sorts and not all amounted up to the same evil as the Egyptians enslaving the Jews, European and American slavery or slavery that goes on today in form of sex slaves and the like... those are indeed evil and God did speak against it. He even spoke against usury. But because of the proximity of past American slavery here we tend to think of it always in those harsh terms. But indentured servants were those kind of slaves. They worked for the boss, got paid some minimum wage... or they worked "by some order" to pay off their debts. And there were different levels of indentured servanthood at that. A sharecropper or miner who lived on the industrial site with their families would be a good equivalent of that type of slavery (indentured servanthood) back then.
Speaking of racism... Moses married a black woman... Solomon had black women as wives... a dark-skinned man helped Jesus when He was carrying the cross. I think that we've already discussed scientific racism and how our current understanding of races came about... even though there were different kind of white races in Europe according to science in Darwin's and Galton's day. Not to mention the Eugenics of Sanger and Hitler which was based on Darwin and Galton.(Actually, Darwin was pretty much a puppet of the European politics of that day).
Sexism... When God created Adame and Eve... He said "let them have dominion of the earth"... not him but "them". The sexism that you are thinking of was custom norms outside of the church before the church was even created. It's just that they had to walk a fine rope as to not offend the society because those people would go and have gone to the authorities. As Paul had stated, they came "to spy out their liberties". They were already being persecuted so why add fuel to the fire. That is pretty much the basis of why Paul talked about decency and order...