It's a good analogy from a technical standpoint, with the "minor" difference that in most situations pilots have a lot more time to react than the driver of a car. Which makes it very different from a consumer standpoint
Even if true, when you talk about consumer marketing, none of that matters.
I don't have name for it, but there's a whole class of bad-faith, deliberately misleading statements that exploit the difference between common and technical understandings (e.g. say something you know most people will inaccurately interpret as X, then fall back to the much narrower Y when challenged).
In a similar manner, if some computer system in a car holds the steering wheel straight and the speed constant, it's working just as well as a plane's autopilot even if it crashes into a parked car at full speed.
Apparently it also must be engaged above 28000 ft. Imagine if autonomous vehicles were so good that they were required to be used while going at speed on the highway.
a) Pilots have certification and training which includes proper use of whatever ‘autopilot’ that plane has.
b) Even so, the name still “over-promises” in an arena where doing so risks lives. So it should never have been called that even on a plane. Let alone on a car sold to consumers with little regulation.