Errrrrrm, would you be happy if your doctor had AIDs and was dealing with your insides?? The risk is negligible, but that risk exists... it makes sense if you think about it. It would scare ppl witless and really piss them off, most of society dont have a clue about these thigns and are like "oh no AIDs, he would so kill me with that!!", and govt enacts on the lines of public opinion (of that is the duty of government), so therefore it stands to reason it's banned.