It'd be nice to paint a broad stroke like that, but we can't ignore the flaw to every solution: the exceptions - those who were infected by mother-to-child, blood transfusions, possibly rape, etc. Sure, perhaps most people get it from risky sexual behavior and sharing needles, but to the exceptions rules like this would be "unfair."
Why stop at HIV then? How about HPV, which is incurable and some strains of which carry a high risk of cancer in women? (I recognize there is a vaccine, but it does not prevent all strains.) If a nation is worried about a burden on its healthcare system, do cancer patients get denied entry as well?
What about someone with poor vision? He/she might get behind the wheel of a car -
despite doctors and lawyers and authorities sternly telling him/her not to - and kill a bunch of kids crossing the street at the elementary school down the corner. Where does it end?
I'm actually on the fence on this issue. The language school I attend - the biggest and best known on this island - requires an HIV test prior to entrance, which I think is absolutely ludicrous. Two thousand students - myself included - nonetheless submit to it every year, but a few of my classmates and I voiced our opinion to the director. Elsewhere in this country, HIV-positive students have been denied entry to public schools, and some others have been declined for medical treatment at local hospitals. The government has started providing treatment for patients, but more importantly, the education is lacking severely.
A lot of countries already have restrictions on HIV patients.
http://travel.state.gov/travel/tips/...ures_1230.html