I learned it from Anthony Keidas of the Red Hot Chili Peppers. He told the crowd at the Landmark Theater that night (triple bill with Smashing Pumpkins and Pearl Jam).
Their album Mother's Milk has a song called "Magic Johnson" - the whole band was bigtime Lakers fans but they had stopped playing that song live due to some sort of argument/fallout with Magic about a year before. When Keidas told that crowd that Johnson had HIV, everyone started screaming for them to play the song, but Keidas said something to the effect of " that."