HIV positive people on medication, cannot spread HIV. It's factually safer to have sex with an HIV positive person on meds, than a person who doesn't get tested and doesn't know their status.
This law exists so that HIV positive people who cannot spread the virus are not legally obligated to tell others they have the virus.
Please learn more about what it means to be HIV positive, and the discrimination that comes with it before making these horrible disparaging comments.
Undetectable = Uninfectable (u=u) maybe a good thing for you to Google.