So the officer came into this with probable cause, and the evidence of the skidding just added to this. Essentially, the Supreme Court saw this as a motor vehicle stop and it was governed by these rules. In this case, the officer has a right to ask for a license to drive the vehicle even when it is parked, because it is obvious and reasonable to expect that the driver would move the vehicle at some time in the immediate future.
This isn't the case for a pedestrian, who has no need to possess a drivers license and last time I checked a SSN is not allowed to be a legal ID. The officer in the photographer's case stated that he had no reason to suspect her of a crime and thus, no expectation or reason to detain or harass her on the face of it.
Now for the deeper story. Think photographer. Where is this photographer. What is she doing. Remember we are at war and people are observing potential targets. This is a valid reason for an officer to notice and request identity from an individual who is just a seeming pedestrian, and very probably one of the unstated sources of the reason the office became interested in the first place.
And that's another problem.
We "drove" conveyances in this country for many decades without having to present a "license" to govt. agents.
In a free society, it is a fundamental right for people to peaceably travel from place to place without being interfered with or detained by govt. agents.