I'm not messing with morality here. It's accountability for irresponsible acts.
The issue is
unprotected sex. Straight or gay or bi...anything else in this day and age is irresponsible...unless you know for a fact that your partner is clean and/or monogamous and not an IV drug user.
AIDS didn't cross over from the original gay population until bisexuals and intravenous drug users were touched. Then it was on to unwitting hemophiliacs/transfusees and straight people who might have caught it from their dentist and other ways.
In all likelihood, AIDS would be classified as an exotic disease today if gays didn't bring it into the world.