The reality is they may not know exactly what was obtained, but they do know it wasn’t anything they don’t collect (like DOB, SSN, etc listed in the message). Instead of looking at this purely as a CYA message, instead looking at it as informing you as soon as they had any idea your information may have been impacted instead of waiting weeks/months to inform you. Don’t let perfect be the enemy of good.
For me as the driver of not one of these cars, I think the driver monitoring and sheeting is perhaps one of the most important parts of these systems. I 100% want your car to scream at you for not paying attention while use the driver assist features because it’s such a common and easy thing to do (if it works 99 times without issues, human nature is to assume it will work that 100th time, so checking that email from work real quick is probably fine). When the consequences of a driver failing to post attention while using these systems is potentially other people dying in a horrific crash, your discomfort at an alert because you happen to be a perfect driver that never does other things in the car while driving doesn’t matter.