Normalizing what is "unnatural"? That is the crime that you seem to find unforgivable.
So would you consider in vitro fertilisation to be unnatural as well? That is the process by which egg cells are fertilised by sperm outside the body in a test tube. That seems to me to be incredibly unnatural by your definition. Would you argue that heterosexual couples who use that practice are just as perverse as gays? Would normalizing that practice in society for the few people who do it be as terrible as homosexuality?