People were also repulsed by mixed-race marriages and claimed they were unnatural. Also apparently not everyone is repulsed by same sex conduct, in fact millions upon millions of people find it very attractive. Your personal repulsion in no way is determanative of something being unnatural. Lying is also acceptable under certain circumstances, there is nothing immoral about lying to save the lives of others. That would be a completely moral lie. Being mean might be called for in certain instances, though admittedly rare. Drill instructors are pretty mean people, but it is necessary for training a soldier. Incest is a tricky one, because I also get an innate feeling of disgust from it and it does indeed seem wrong to me and the incest argument definetly presents some problems. However we all obviously can not figure out what is wrong on our own because we obviously have very divergent agreements about it. I am completely heterosexual and have absolutely no attraction to any man, and while I have no personal attraction to men, it does not bother me if other men are attracted to each other and engage in private sexual conduct. Heck I am even so vain that I could care less if a homosexual man is attracted to me, I might even be insulted if he wasn’t because maybe he thinks I am ugly

I am much more repulsed by the idea of obese people having sex than I am two men having sex, but obviously my repulsion should not be a deciding factor in what is and what is not moral behavior. You are arguing from mere social convention, not something that is innately inherent in all people. Classical Greece and Pagan Rome found homosexual conduct perfectly natural, now how is this possible if everyone is repulsed by it? Because it has nothing to do with its innate morality, it is simply social convention.