Actually, intentionally infecting people with a virus wasn't "a thing" until HIV, thus specific laws against it were not really required. Obviously, anything you do to intentionally harm another person, including infecting them with a dangerous virus, is prosecutable under the law, up to murder. Plenty of people who are infected with HIV and Hepatitis C have been given lengthy prison terms for spitting in peoples faces. Up to 35 years. A few far left states like California have passed laws to protect people infected with HIV who knowingly expose a person. Maybe this poster identifies with those people who infect others with AIDS. It's a right ya know, just like spreading COVID-19.
I think you nailed it with the poster.