Why? Because it was proposed by a Republican president. (and continued by the presidents who came after him).

But mainly because it only Saved a couple of million Africans.

We probably had HIV when I was working in Zimbabwe, because we had people with Kaposi's sarcoma and people who died of what seemed to be a failure to fight ordinary infections in what should have been healthy people.

Here is the CDC page on PEPFAR in Zimbabwe:

you have to test people, and test their contacts, and put them on treatment.

The hospital where I had worked had an outreach program, and our sisters had a clinic in Harare, until it was destroyed by Mugabe in his Operation Murambatsvina program which was explained as a way to clear out the slums, but in reality destroyed the areas that voted against him.

Right now, the international public health programs are getting a lot of hostility, much of it hysterical and political in origin. 

The coverup of the Covid origin and the initial denial of the WHO head that it could be spread person to person is part of the reason, as is the over reaction by governments to the epidemic that shut down the economy, something that will kill a lot more people than covid.

like the boy who cried wolf, the WHO has lost credibility and some see their plea (send us oodles of money ) as another power grab. 

Yet one does have to remember that this program has Saved Millions of ordinary Africans.