Try reading the history. IV drug use wasn't even considered until the 1983. It had been around since the mis 70s. When it broke out to all 6 continents, it was mostly homosexual men.
"A doctor was treating a gay man in his 20s who had pneumonia. Two weeks later, he called to ask for a refill of a rare drug that I handled. This was unusual - nobody ever asked for a refill. Patients usually were cured in one 10-day treatment or they died" - Sandra Ford for Newsweek 4
"Dr. Curran said there was no apparent danger to non homosexuals from contagion. 'The best evidence against contagion', he said, 'is that no cases have been reported to date outside the homosexual community or in women'" - The New York Times 11
In June a report of a group of cases amongst gay men in Southern California suggested that the disease might be caused by an infectious agent that was sexually transmitted.19
History of AIDS up to 1986
Get it right Redress