You know, that just is not true! Granted it certainly came to light in the 80's in the gay community environment of San Francisco, but it's certainly spread beyond just gays. It's into the drug users and in some cases into the heterosexual community as well as some blood recipients. Also remember it was not a homosexual disease in Africa. Now, I will say, for the major part, it is a preventable disease in that, for the most part, it has to do with the decisions one makes in their life style, but it is no longer just a homosexual disease.
That may be, but the spread of it is spread nonetheless by rape, anal sex, drug use, and otherwise immoral behavior.