I'm not an owner, but even I know that the Adaptive Cruise control is for use on clear highways and can't cope with much.

This was a situation where the driver plainly needed to take over, had plenty of time to take over, and the issue was sufficiently obvious that even a non-alert driver who was looking forward would see they needed to take over.

There's an argument to be made that relying on partial automation is a fundamentally bad idea because the driver will not become sufficiently alert in time to save themselves. This is not an example of such a situation.