I didn't read that as a suggestion there's some secret AIDs vaccine kept locked away by big pharma, rather that many have died because of lack of access to the treatments that exist.
Yea I mean, it's part of a lyric from a song so it's debatable whether it's meant to be taken literally or if he just needed something that sorta rhymes:
A toast to the dead / For children with cancer and AIDS / A cure exists and you probably could've been saved / Sad to see medicine divorce morality / Corporate home-wreckers pimpin' up the salary
