Somewhat ironically, autopilot for airplanes is more less attitude/speed holding for most history. More modern systems can now autoland or follow a preprogrammed route (the flight plan plugged into the FMS), but even then changes like TCAS advisories are usually left up to the pilots to handle. Autopilots are also expected to give control to the pilots in any kind of unexpected situation.
So in a way tesla’s naming here isn’t so off, it’s just the generic understanding of the term “autopilot” that is off somewhat. That said, their system is also not doing much more than most other level 2 ADAS systems offer.
On the other hand, Elon loves going off about Full Self Driving mode a lot, and that’s absolutely bullshit.