I am 5'2"; is it then a sin that I am not living my life as a 5'8" woman? I took this body so that I could live out this particular physical life and experience the particular lessons required for my soul. Not only do I live this life in my own way, but other people react to me, based on my appearance and personality. Would that not also apply to any homosexual? It is simply a costume worn for our Earthly stage performance. We are the soul, not the body.
Religions and those in power in those religions here on Earth have written the various guidebooks (the Bible, etc.) with their own Power in mind. So, various groups have been judged as sinners while others have not. These writings are for keeping "the sheep" in order here. These books make life difficult for those who live outside the definition of the norm because it makes 'the norm' group of people into very judgmental types, smugly sure of their aspersions on others -- they miss the point of loving their fellow human.
The body enables the soul to have an Earth experience which is a PHYSICAL experience and all that that entails; the soul alone goes beyond.
Just love and be loving; what else is there in the end?