How could this end the argument? Even after having read that, I still believe homosexual acts to be a sin. Don't get me wrong, it isn't an unpardonable one. What I define a sin as is anything that causes a person to stray from God's will. For the record, no one sin is greater than another. A lie is the same as murder to God. The logic being that God is a perfect being. ANYTHING that is imperfect is not up to God's standards. There are no degrees of perfection. Either you are or you aren't. The only thing that saves us is God's grace and the fact that Jesus Christ paid the blood debt for our sins on the cross. A perfect man took the blame for all of my sins. Past, present, and future. He took the blame for all of your sins as well. The trick is that you have to accept the forgiveness and grace.
I am the first to tell you that though I believe homosexuality to be wrong, I am no better than anyone else out there. Seeing a large number of people sinning does not diminish the fact that I believe it is a sin.
I also believe that homosexuals can be saved just as easily as I was. The main difference is that striving to not lie, cheat, or steal is a bit easier than trying to deny sexual urges. Compound that with the fact that being gay affects many parts of your lifestyle as a whole. It is very difficult to be able to control something this pervasive, even if one had the desire to. Deciding to try and not lie is a lot easier than deciding to try not having homosexual sex. The former affects only the person making the decision. The latter affects those around the person. Especially if we are talking about the partner of said person.
Now, to tackle the idea that God punishes one for his neighbors actions, look into the destruction of Sodom and Gomorrah. I wager we can all guess the nature of sin Sodom was punished for.
Again, I want to make it perfectly clear that these are simply my beliefs, and I understand that my beliefs more than likely don't match up with yours and that's fine. But understand, you are as likely to change my mind about this as I am of changing yours. It is never going to happen. And you know what? That's OK.