Normal people don't care. People who think it is sick is homophobic. Again, thank the countless religions that force the "fact" that homosixuality is "bad" down our throats.
I think most people just naturally think homosixuality is disgusting with or without religion.
And if you're the type who thinks religion is just made up, well, it was made up by people, right? So according to your own logic, most people already thought homosixuality was wrong well before religion; afterward, religions were formed that reaffirmed the idea that "homosixuality is wrong." These religions wouldn't have survived for so long if people weren't already naturally inclined to believe that homosixuality is wrong.