Then I wonder why concert venues have press passes, if the photographers are working from a purely public place?
Grocery stores, shopping malls, and hotel lobbies & conference rooms are not public places either.
The confusion about "public" stems from casual usage vs legal usage.
casual: "I can't be seen in public without my makeup and bra." In this case, "public" just means the opposite of "not at home."
legal: The boat dock is public property but the restaurant at the shore is private property. You can shoot photographs at the dock but if at the restaurant, if management asks you to leave because you're snapping photos, you are required to comply.