God created the original, perfect Adam in his image. Adam fucked himself up. Then we came after. We are the products of Adam.
I don't see why this concept is so hard to grasp. Think of it as a product. God created a perfect device. He then let the device have free will and the ability to replicate itself. The device fucked up, and the imperfect result was replicated, not the perfect prototype.
As far as homosexuality goes, do you have a problem with probably 99% of day-to-day heterosexual activity being a sin too? Because that's what it is.
Look, if I think about fucking the cute waitress bending over that table--guess what? I've committed just as much of a sin as you in blowing a dude, or taking it in the ass. That's just how it is. We're all sinners, and we all sin all the time. We sin in thoughts, words, and deeds. It's not like homosexuals have a monopoly on sexual sin.
So, if you are a homosexual, that's tough. But I don't see it any different as being a man who's basically hard-wired to want to fuck as many hot women as he can. That's tough too. God doesn't see it any differently. It's just a different river to cross, and I'm not going to tell you what to do. You have to make your own choices what you want to do with your sexuality, just like I have to with mine.
The good news is, the salvation from homosexual sin is exactly the same as the salvation from hetero sin. It's salvation through faith in Jesus Christ, who suffered and died for everybody--gay, straight, whatever.