Greg Louganis still has HIV. It isn't something that goes away. He is living very nicely with it, but it isn't something he had, it is something that he has.
In there defense, using the past tense indicates that he had it while he competed as an Olympic diver instead of the possibility of trying to think of an Olympic diver that became infected since then.
This is actually a somewhat valid gripe, as technically the SABER organization basically invented them. But Bill James was a member I believe, and the most famous one at that.