It is actually more likely intended to be a manufactured plague on the gay community at first. The first diagnosed cases of HIV were gay people. In my experience with HIV, the patients have all been gay. That doesn't mean drug users and other people don't get it, but in the US, it has primarily affected the gay community which is why it was such a big deal when Ryan White got it. He was a little boy who was diagnosed with hemophilia who got it from a blood transfusion. He became a poster boy for Hollywood's campaign to prove that HIV wasn't a plague against the gay community. It is blood borne pathogen, so of course it is not a plague against the gay community. It behaves the way any blood borne pathogen would, so anyone is at risk if you are sharing needles or sleeping with multiple people without protection.
The difference is that if it is circulating within one group of people, you are not going to be at higher risk of AIDS if you are drug user. You will be at higher risk of contracting the disease if you are gay because that is the population group it is circulating in and being gay doesn't mean you are a drug addict, which would be how the virus would be introduced to that different population group.
This is an interesting clip of a news report when AIDS was identified. People thought it was cancer.
In fact Len Horowitz's research suggests that AIDS was created in a lab from cancer virus'. It does behave in a way that makes it seem like a cousin to leukemia, but virus' are often overlooked as a cause of cancer even though there are virus' we know create risk of cancer. HPV for one. Epstein Barr virus is another one. It is very likely more cancers are caused by virus' and that AIDS is a cousin of these virus'.