To me, what makes it wrong is the defiance towards God. People have pride, and often (without even realizing that's what we're doing) we act rebellious of God's will for our lives. Regardless of why God says it's wrong, He does, just like regardless why overeating is wrong, it is, or why smoking or abusing drugs is wrong, it is.
Now the good news. Homosexuality is no worse than any other sin. The Bible says that no sin is worse than another so it won't keep one from heaven any more than smoking and overeating (not caring for God's temple) will. A lot of the consequences for many sins are met here on Earth through pain, disease, heartache and so on. (example: in many cases Divorce is a sin, but the punishment for this sin is earthly through emotional pain and scars, financial losses, credit score losses, children's pain and so on.) God judges our hearts, and if one's heart is God's then that is just how it is, and nothing we say to judge them will change that.
And yes, I know I will be crucified in here for my opinion, but eh, that's their right, just as my opinion is my right.
Peace!!