Exactly! Because in the Jeep case there was an architectural failure where the attack surface (the radio controller) was connected directly to the vehicle control system via a CAN bus, speaking bare unauthenticated protocols that were designed before the idea of internet-accessible cars was conceived. So once your initial attack face was compromised, the game was up.

This is the writeup if you want details, certainly I'm no expert on this particular hack: http://illmatics.com/Remote%20Car%20Hacking.pdf

What I'm saying is that Tesla seems to have learned from that experience and gone with a very different architecture where vehicle commands simply aren't accessible to the public-facing computer, from which motor/brake/steering control systems only get general direction (e.g. waypoints).

That's not saying it can't have a hole. But they don't seem to have made the kind of messup that would permit an attack like the Jeep hack.