and everything to do with cutting someone off. Had Car A been previously doing 45 mph in the left lane for some time, then car B came up at 70 mph and swerved, the lane choice of car A would be an issue...but in that case it would be hard to argue that driver A was any more a moron than car B.
I've personally never been bothered by this. Probably b/c the divided highways I travel on are almost always crowded enough to require both lanes to be consistently occupied to maintain a reasonable flow of traffic. The left-lane passing issue is mainly relevant on rural interstates with sparse traffic.