Probably more related to the god-awful infrastructure design in the US, like stroads and an unfathomable tendency to use stop signs for a lot of things they are just not fit for, like to replace speed bumps, chicanes, and roundabouts.
Also the better comparable statistic should be deaths per distance traveled in cars.
No, crashes in the US happen because Americans are shit drivers. They are shit drivers because you get a free driving license with box of cereal. Germany on the other hand has one of the strictest driving tests there is. A German with a driving license has had many hours of instruction from a professional instructor.
In addition, American cars are shit. Lots of poorly maintained and unsafe vehicles on the road with very lax regulation. By contrast, German cars have to pass a very comprehensive yearly safety inspection.