When I bought Autopilot I asked about taking it to another Tesla if I bought one, and was told it belonged to the car. Meaning when I sell the vehicle I assumed I could advertise that I was selling Autopilot with it. Tesla is 100% in the wrong here.
They would be in the wrong if that is what they were doing, but it isn’t.
If you sell your car to a private party it keeps all its options. If you sell it back to Tesla, ie trade in, they may add or subtract options before reselling it.
That said, there have been some screwups, especially with third party dealers, leading to the current kerfluffle.
Then they're selling features for tens of thousands of dollars and what are you buying? Do even they know? Sounds like they're deciding retroactively case-by-case what the original purchase meant.