HIV is more preventable than pregnancy.  There is no magic 'before sex' pill to prevent pregnancy.  The magic 'after sex' pill isn't 100% effective, either. 

 According to his article, 100% prevention does exist for HIV.  And those most susceptible don't even have to change their choices regarding sex or injected drugs.

As far as your earlier inquiry why a non-participant should care about those sexual and drug choices, one of the strongest health arguments constantly trotted out is the 'impact on health care costs".  50,000 HIV new cases per year are a significant 'impact'.