One issue that's usually overlooked is that once someone has AIDS, THEY don't have anything to lose, and are therefore the most likely to continue in unsafe practices. Saw one movie made by homosexual men as part of a gay/lesbian film festival (no I'm not and it's a long story as to how I ended up seeing it), and there were several interviews with AIDS patients stating that they generally didn't tell their partners they had AIDS because it would ruin the mood. I think approximately 50% of AIDS infected homosexual men, according to some studies, have stated that they would lie about having AIDS in order to have sex with someone. Haven't seen any stats on straight men, but I know a LOT of women who have gotten herpes & other STD's from guys who didn't tell them a thing.
Not only then, but there are gay men called barebackers who actually chase the bug. Freaks. Absolute freaks.