[karatestomp]

The short and slightly oversimplified answer is that one level or another of our government has all the same info on us most other countries do—if they don't, they can sure as hell ask any of several companies for it—but various interest groups demand, for a few different reasons, that they pretend like they don't, mostly in the name of some notion of freedom or advocacy of same (for the latter, see: making income taxes annoying for hundreds of millions of people only because some folks want them to be annoying)