I'm not at all defending homophobia (I'm gay, plus it hardly matters, I don't care at all what anyone's sexuality is, so long as all parties consent, it's all good), but there's a phrase along the lines of "The bible says a lot of things," I figure that seems to fit here. There's no denying that at least to the jewish community which existed during the time of the writing of Leviticus, homosexuality was seen as being a definite trait of the Babylonians, who I believe had conquered them, and weren't they actually taken and split up? That seems to happen to Jews quite a lot, at least historically. Anyways, the point is that at the time of the writing there was probably a strong desire to preserve their Jewish identity at the time. Listing homosexuality as forbidden would certainly be a way to ensure that they weren't, let's say fraternizing with their captors, so to speak.
Now, I may think it's unethical, but that's just me, and it's important to keep in mind that the bible is not just the work of one author, it's a collection of writings that were written over the span of thousands of years, and that's with significant editing! Naturally it's going to say, well, quite a lot of things, and there'll be quite a bit of context lost, and lots of it lost in translation. They aren't going to say "Here's why we wrote the third word of Rule A-12, Subsection 14, Line 8," so we have to go on what we know historically. I respect the bible as a religious work, and as a former Christian I can say that yes, there's definitely some good in there, and it did do the trick of driving me to get my s**t together. Except here's the problem: I only read the nice parts. I like to think that I was striving to follow the spirit instead of the letter of the law, let's put it that way. It's for that same reason that I realized I could be moral and good to others without feeling like God was one sin away from blowing my spiritual brains all over the pavement of hell for disobeying him.
Christians against homosexuality, I understand you feel like my "choices" (by which I mean feelings that come naturally to me) aren't what Jesus would have me do. I understand you think that somehow my life is unfulfilled, perhaps you feel like it's a waste or a shame, or I'm not living up to my potential. That's just fine, you have every right to think whatever you want about me and my life, go right ahead, I won't stop you. I only ask that you first of all at least devote a little time to really closely reading what it is your religious texts are spreading, beyond just the interesting stuff about how God loves and tolerates everyone and is going to forgive everyone. Second of all, please understand the boundary line between moral restrictions that you place on yourself and moral restrictions that should rightly be placed on everyone. It's not fair or right for you to place your own moral restrictions on people who simply want to be treated as regular citizens. I'm not accusing readers of this of personally setting up the conditions in which we now live, but I am saying that the next time you have the chance to change the country, please do what you can to allow others the same validity you would want and probably enjoy yourself.