I don't think it's that obvious though, once the anger/outrage melts away.
The nag also serves as an attentiveness check: If every 10 seconds you expect the car to tell you "tug the wheel" and you've got a few seconds to respond to that before the alerts escalate, it is going to at least keep you more engaged with paying attention in the context of watching for alert nags.
I'm not an expert on human behavior, but anecdotally there's a pretty big difference between 10 seconds of distraction vs allowing drivers to go 2-5 minutes between nags (on certain road conditions currently with AP1 or AP2). The latter is practically enough time to watch a music video before the car reminds you maybe you should be looking at the road.
FWIW, I'll admit to not being a perfect driver: There's been a few occasions where the car flashing the Hold Steering Wheel alert was when I suddenly realized that I had zoned out for a while. How long was that? Who knows, probably as much as 2 minutes. I hope not.
Just playing devil's advocate — I think there is some merit to the idea that more frequent nagging results in a more engaged driver. But yeah, as someone that paid $8000 for what's supposed to be the most advanced continuously-improving ADAS, it kind of feels like BS as well — I also would rather they make actual improvements to automation safety rather than better babysitting of inattentive drivers.