What's scary are the people who willfully infect others with HIV, fully knowing they are infected themselves. They do it out of spite, out of anger that the world's been unfair to them for giving them an incurable disease. That, or they just don't care as long as they get their libido satisfied.
That actually happened in the USA during the 1980s. At that time, HIV was more or less an unknown disease and there was no ARV treatment available. The homosexual associations in California urged the HIV infected gays to donate blood, so that more of the general public would get infected.
Their logic was that if HIV remained confined to the homosexual community, there will be no government funding to fight the disease. On the other hand, if it affects the general population, people will take care more about it. The tactic worked, as a large number of non-homosexuals became infected with HIV through blood transfusion.
Well maybe this logic had place in 80s. I hope it won't now.