I don't get it!
This makes absolutely no sense to me as the very term "autopilot" comes from aviation, where it is a device that holds the heading and possibly the altitude of an aircraft constant. It is not used to mean a device that is capable of monitoring air traffic or other hazards such as terrain or weather. When a plane is flying on autopilot the actual pilot is still responsible to all of these things. It seems that the problem is not the word, but the fact that people think it is something it isn't. I believe that Elon deliberately chose the term because it emphasised the fact that it was NOT a self-driving system, but something similar to the aviation device of the same name.