I'm not homosexual, and as such, I'm not exactly qualified to answer it from their point of view.
But my views on that are, to be blunt: How can someone who claims to love God choose to live a lifestyle so contrary to what He's all about?
That's true for any "sinful" lifestyle, whether it involves alcoholism, domestic abuse, or whatever the case may be. But as I said before, only God can truly know a person's heart. Other people can only judge a person based on their actions, which is why we're told not to judge people at all. However, in loving others as ourselves, we ARE instructed to judge the person's actions. I.E. say I steal something, for example. I may become disappointed in myself for stealing. I may grow to hate the fact that I stole (whether because of the punishment it will get me or because I truly hate the fact that I stole is another matter entirely, but nonetheless). But rarely will you find a person who says they hate themselves because they screwed up, and usually they have other problems. You find people who hate the fact that they screwed up, but they don't hate themselves for their screwups. "Hate the sin, not the sinner," so to speak.
As for the sacrifice: "When the Heavens pass away, all your scars will still remain, and forever they will say, just how much You love me."
Let me list for you some of the ways in which the actions of Christ were indeed a sacrifice to Him:
First and foremost, if you had ultimate, omnipotent, uncontested power over the entire universe, how hard would it be for you to give it up? Christ left the Heavens to be a man. Last time I checked, God > Man.
Next, not only did He give up that, which in itself is a huge sacrifice, but He came as a poor carpenter's son, not as some grand, conquering king with an army! He lived in humbling poverty. He was born in a barn! He was tempted with the same temptations anyone on Earth faces, only he never gave in, a feat which no other human being in existence has come close to achieving.
And finally, His torture and execution for crimes against men which never even took place, and crimes against God which WE commit(ted). Make no mistake. Christ did not want to go through with it. He even asked God the Father to call it off if there was any other way His master plan could be fulfilled. Yet He was obedient till death, and then some.