The "Catholic issue" does contribute to the spread of AIDS in Africa, but it is simply not the only or main reason.
I studied the spread of AIDS in Africa as part of my degree and while conditions have changed since then many of the factors still hold true.
The main route of AIDS distribution was along the long distance trucking routes as drivers would stop off and visit prostitutes on their journey. AIDS soon spread in a largely linear fashion along transport routes. Once distributed along these routes it soon spread elsewhere as infected drivers slept with their wife of partners.
Certainly the Papal effect on the use of contraception is unhelpful in preventing the spread of the disease, but not everyone in Africa is a fee paying member of the Roman Church and contraception was not really used in Africa anyway.
There are cultural/macho issues that often mean contraception is not used. There is ignorance and mystic/tribal beliefs that also make people think they cannot catch it. There is a culture of multiple wives in certain parts of Africa.
If Catholics stuck to the core massage from the Pope (as Jiglo pointed out), they would only ever sleep with one partner in their life. How many Catholics in Africa or elsewhere have stuck to this teaching 100%? Not many is my guess. I suspect many who defend the Pope and the Catholic Church around the world also break the rules. . .such is life. . . .Jesus was "perfect". . we are not.
The facts are AIDS affects all societies, but Africa is blighted for many reasons . . cultural, religious, education & economic factors are all important.
It cannot be oversimplified, it is deeply complicated and very sad.
Excellent post. Well written and informative.