You're illustrating exactly the problem I'm outlining. You're conflating adaptive cruise control with self-driving technology and they are not the same.

ACC is a short-range speed-matching protocol driven by ultrasonic sensors. It modulates vehicle speed to maintain a set distance between vehicles with zero delta-V. Assuming the sensors are good, the system itself is simple - the complaints you have about Subaru vs. anybody else are a matter of driving feel, not a matter of function and overall, the task they accomplish is theoretically simple. The instrumentation is critical and robust, to be sure, but from a systems perspective it's basic.

Tesla's Autopilot will pass the car in front of it if you hit the turn signal.

Subaru will beep at you if you stray out of your lane. That's it. They're still maintaining a status quo, throwing warnings at you for deviating and providing instrumentation to help you make it through your commute alive. Tesla is legitimately driving for you. What they're doing is at least a couple orders of magnitude harder, and they're dealing with an environment with radically higher delta V. ACC is a driving aid that fails back to safety. Autopilot is an active technology that - as demonstrated - has no failsafe.

Tesla has not made this difference clear to their consumers.