People with HIV/AIDS will travel...or not

Apparently, many countries will deny you a visa if you are HIV+ or have AIDS - including the US. What is the rationale for this? That this will prevent people from entering a country and infecting all the innocent people there? Or is it really about securing resources for wealthier countries? I'm sure that it is a bit of the latter, but also fear of the former. It's interesting that, as the article points out, conferences about the global AIDS crisis cannot be attended by people with HIV/AIDS.

Apparently the US does grant waivers for people with HIV. However,

If your name is entered and flagged in CLASS and/or TECS as being HIV positive you may be barred from future entries into the United States - and - You may apply for an HIV waiver for another future visit/event. However, obtaining the waiver may be difficult.

And, of course the individuals who get the waiver will have better access to resources and knowledge of this. Which means that this particular policy prevents people of lower socioeconomic status from entering the country. And these are most likely the ones who have the greatest need for medications and could contribute greatly to conferences on the global AIDS crisis.