Brian's point about loosening the definition of aids is also correct. In most instances, the person who contracts aids already has a decreased immune system because of other diseases. In the US, homosexual males frequently eat each other's feces, and "gay bowel syndrome" was well-known throughout San Francisco prior to the aids outbreak. In Africa, frequently people bathe, urinate, crap, and drink within yards of each other in lakes and rivers. In almost all cases of "heterosexual" aids, you'll find other factors, such as drug abuse, hemophilia, bisexuality, or other "dirty" sexual techniques (those which transmit feces, etc, from one person to another.)
Humans weren't meant to ingest urine and excrement; it's just not healthy. If people in general began cracking open the sewer pipes in the streets and started eating the contents thereof, then even the healthiest of immune systems would take a beating. Yet it seems that homosexuality in practice does just that.
Oh, This is so romantic I want to vomit. The though of butt plugging is disgusting but the thought of eating your lovers feces is atrocious.