Sure, no one's suggesting they _should_ be altered, but evidence from the entire world suggests that most people (partly in a political context) are too dumb to

Sure, no one's suggesting they _should_ be altered, but evidence from the entire world suggests that most people (partly in a political context) are too dumb to understand the concept of the damage done by a car-friendly/human-unfriendly city design. So external barriers like the one described here tend to be the only defense.