As long as everything is done so that they only threaten themselves (and ensure that they only breed among themselves), we just have to sit back and let evolution do its thing.

Within a few generations, this particular brand of idiocy will be completely wiped out. Guess what, HIV kills people and decreases their chances of reproducing. Well, OK, it doesn't kill directly, but it's all the same. You simply can't live without an immune system.
That said, I never heard of people who would actually be OK with HIV. I did hear of people seeking sex with people who have HIV for a thrill (dunno how that could be arousing, but with some people, you never know...). All the same, as far as I'm concerned.