Lets look at this from a slightly different point of view?
Dissipating as much energy before it hits the skull is an obvious advantage to pedestrians, (or are you going to dispute this as well?).
By dissipating energy you reduce the amount which can cause damage to your skull and internal organs (following the bit about pedestrians so far?).
By placing a compressible material between your head and the ground, some of (I never stated all, referring back to my point that it isn't a miracle "cure" ) the energy will be removed. This will place a pedestrian in a better position then if it was their skull which did the "compressing".
Once again, you wouldn't drive a car without airbags, you wouldn't drive a car without crumple zones, but maybe you should consider a helmet as well given the large numbers of hospital admissions through head injuries to car drivers and passengers that still occur despite all ofthis.?
It's basic physics
In a pedestrian fall however, the helmet which is in question will be one of those circumstances where it is advantageous.
You still haven't explained why you have a fixation on cyclists wearing helmets, yet feel it unnecessary to prevent head injuries in the more vulnerable groups that suffer far greater numbers of head injuries.