It's a news story about the scientific study that was complete by "The Lancet" and The University of Toronto. Furthermore, there have been countless other studies about other parts of the worlds that validate this belief.
As for your firearms analogy, I'd say this. Protective armor doesn't guarantee you won't be killed by bullets or shrapnel. But, it's an illogical conclusion to draw that protective armor isn't a good idea. And just like no Captain or General guarantees 100% effectiveness with protective armor, I've never seen a responsible health care worker ever claim that condoms were 100% effective in preventing any STD or pregnancy.
Prophylactic or preventative measures are always a good idea even if the prevention rate isn't 100%.
Big difference. People don't put on protective armor so that they can walk around in a hail of bullets. They put it on so that they can survive the rare bullet that may hit them. Most people who put it on never need it.
If a man in Africa has sex with a prostitute once a year and he wears a condom, then his odds are much better. If he has sex with a prostitute and condom twice a week, then he is only postponing his infection.