I don't think this is the mindset you think it is, be it American or not (I'm not American myself and can see his point, but I read it differently than you (maybe I'm wrong and it's the way you say in fact, as I said first, "I don't think this is it"))
Instead of a cars vs pedestrians thing it can just be seen as a flow vs flow, it could be some crossroad with endless streams of cars both ways, one being given some higher priority than the other.
It happens quite frequently, when I am part of the prioritary endless flow of cars, and there is even just one car (it doesn't matter if they are many or not) on the non prioritary side, and if the speed allows it where it happens, I usually slow down and give the stuck car a chance, delaying many just for one.
But I don't see it as 'why one person should delay thousands', I see it as why should one person be stuck four hours so none of the other side is delayed a few seconds.
The same thing is true for endless stream of pedestrians
Yes, hundreds of pedestrian would stop or slow down just to let pass one car with 2 or 3 people in it, because, specially for pedestrians in fact, most won't even notice, and for those who 'actively stopped' right by the road, this is a very minor inconvenience, a couple of seconds, vs several minutes for the people in the car.