It’s amazing how people have selective amnesia. Yes, Luke did throw away his saber in ROTJ, but a few seconds before, he was about to kill Vader. And a few minutes before that, he’s prepared to “strike down” the Emperor, only to have his faithful apprentice intercept the attack.
I would call that a character arc. These things didn’t happen in a random order. Luke get’s goaded into using force, first by Palps, then by Vader to the point of almost killing Vader. Luke realizes he’s about to follow in his father footsteps, and composes himself, tossing away his lightsaber. He’s learned a valuable lesson, and passed the test. A test he then again fails in TLJ.
This invasion of privacy stuff is nonsense. Luke isn’t the NSA. Was it an “invasion of privacy” when Vader mind proved Luke in ROTJ?
Eh, yeah, Vader is the villain. Either way, Luke was fully awake and aware at that point in time, unlike Ben Solo.