The headrest tilt is tailored to allow the automaker to excel at EuroNCAP, NCAP, NHTSA, and IIHS crash safety. It basically guarantees no single individual in the world will be comfortable sitting in the car; but it also mitigates the risk of the carmaker receiving a exceptionally horrible neck or head rating for a crash test.
NHTSA (USA National Highway Transportation Safety) uses a 6' 2" dummy that weighs over 220 lbs and crashes a second car with a 5' 9" 170lbs. These simulate men, and NHTSA doesn't even bother rating head-injury and opts simply to "raise a concern" if head trauma is too high during the test.
IIHS (USA Insurance Institute of highway Safety) uses the same dummy for frontal tests but switches to a 5-foot 110lbs petite woman/teen sized dummy for side tests. IIHS focuses on side-impact damage and use the very diminutive dummy because side impact tends to put smaller people at risk the most. I think the logic is that the driver is usually the larger person while kids and wives will likely be smaller than the driver. And the driver tends to protect themselves on instinct. Anyway, the seat/headrest need to position the dummy's head into an optimal spot for the side air bags on these tests. They don't test dummies crashing with a gangster lean. They test the normal rudder-diagram-seating-position.
I think EuroNCAP uses the same dummies as the USA; but there is a EuroSID-II weird dummy (it doesn't have forearms) that are used in some tests. I forget the seated height of this dummy, but I recall it was a different seated height (probably some feet-to-metric conversion wonkiness) than the previous dummies.