If people are Anti HIV as the cause of AIDS then they must be either racially or homophobically motivated, as nobody can possibly look into the literature or actual studies on the subject and come out of it not believing it. It is very easy for people who hates blacks or gays to simply assume they implicitly are more likely to get a disease.
AIDS denialists are a mixture of lunacy and homophobia, make the percentages of each whatever you'd like. That's the formula though, nobody that is on the level and isn't specifically against a certain group of people believes this garbage or even spends time acknowledging its existence. Like other truthers, AIDS deniers are just a bunch of crackpots that should be dismissed.
Some denials are based on racism and homophobia. It's pretty clear that there is a scientific consenus that HIV causes AIDS. Some denialists claim HIV is a myth, and others that it is a disease but that the AIDs symptoms result from drug use, malnutrition and other risky behaviors. Still others insist that HIV is harmless, or doesn't exist. Others claim that AIDS researchers are criminals and liars. Denialists may claim that heterosexuals don't become sick from HIV and millions of Africans aren't infected. Some of the denials are rooted in fear of dying. See http://www.theguardian.com/science/blog/2012/feb/21/death-denial-hiv-aids
AIDS denialists views are based on racism and anti-gay beliefs. Most people deny something that they do not understand for themselves. Most people choose to ignore the real facts and place the blame on other groups that have nothing to do with it. I think that the first AIDS transmission happened between monkeys in Africa, why are we not blaming them?
I do not believe AIDS denialists views are based on racism and anti-gay beliefs. It takes a special kind of person to dispute clear scientific and medical evidence and that is exactly what AIDS denialists do. I'm sure there is any answer for their denial, but I doubt it is solely based on racism and anti-gay beliefs.