@FS - an interesting analogy, but I'm not sure it's quite so straightforward; if one considers a manual (standard) transmission, then the relationship between throttle position and speed is only monotonic for any single gear, and to accelerate further one must change mode - i.e. gear shift - and in order to do so one must reduce power in order to clutch, shift, clutch then apply power again.
Now this is entirely natural and instinctive for someone TRAINED on a manual, but for someone who's only ever driven an automatic, the notion of decreasing throttle to accelerate is of course unnatural. Yet there are if anything, it seems, more errors in automatics - how many accidents does one read of where people stupidly leave the car in-gear in an automatic and go barrelling through shop windows?.
Similarly, one cannot decouple the accelerator and brake pedals; there is an implicit requirement to "disable" the "accel" mode - by lifting one's foot off the accelerator - when applying brakes. And vice versa. Yet I personally have driven a hundred yards or so with the parking brake on while trying to accelerate and thinking "bit sluggish today". Now it turns out it was my brain that was sluggish, but there's nothing inherent in a car's controls that prevents mode confusion; again, in theory it's trained out, but my training failed that morning....
Regarding the AB AT, I'm noty sure its such a grevious violation of the design principles, especially compared to other types. As I understand it the mode change on the throttle which was not retarded occurred because the OTHER throttle WAS retarded. This seems analogous to pressing the brakes, hoping to slow down, while not really letting up on the gas. The aircraft receives an ambiguous signal as to the crew's intention, and tries to respond to that ambiguous instruction regarding speed control, just as a car would apply throttle and brakes in the analogous condition. In both cases I find it hard to fault the design for not understanding what the operators actual intent was.