Nothing is easier, more intuitive, or less distracting, than scrolling on a proper multi-touch screen.
Of course, needing multi-touch to do scrolling is a pretty major failure, too.
But rather if you offer touch scrolling you’ll also want pinch to zoom.
“Spectacular failure to apply even the most basic common sense” is a pretty strong position. In my experience with actually using a fantastic touch interface for navigation, and having tried and hated using nav systems in expensive cars in the past, where I’ve had to resort to using my phone for nav, I am equally strongly of the position that proper multi-touch nav on a large screen (Tesla Model 3) is safer and easier than any kind of button based nav system.
Now, sure, I can see how a large touch screen might make a better interface for navigation only, as long as you are stopped and can use it without having to look at the road. But I know of an even better interface -- give me keyboard and mouse, and even with desktop Google Maps I'll get routes faster than with any touchscreen system out there.
But of course 1) mouse/keyboard in a car isn't very feasible, and 2) that touch screen, since it's already there, is being used for controlling other systems in the car, too. And that is a problem. Anything that may need a quick adjustment while you're driving (and in real world, of course, that includes things you shouldn't really be doing while driving...) should be doable with muscle memory and at most a quick glance. Touchscreen doesn't do that, so I think it clearly does fail the common sense test.