Sex isn't wrong. It just so happens that it can lead to HIV infection. If you wish people get infected, you've created a moral loop that just punishes people because you enjoy watching people suffer. Congratulations, maybe you do have a handle of conservatism-as-practiced, after all.

It'd make just as much sense to threaten to kill anyone found in public without a blue towel: you'd get the satisfaction of righteousness indignation and the honour of killing lots of people for completely arbitrary reasons.