Of course I.V. drug users transmit it when they share their needles, but you are correct. Heterosexual AIDS is a myth.
Much like the queers, Africa realized that it could get on the AIDS bandwagon, by classifying everything from Malaria to Pregnancy as AIDS.
The CDC tracks IV transmissions separately from heterosexual transmissions. The 175,000 heterosexual transmissions excludes IV drug users. Do you have a better source than the CDC? Convincing heterosexuals that there is no risk of AIDS transmission from sexual intercourse is not a very good idea.