People are copyrighting the composition of the photograph, not necessarily the subject of it.

The original photographer has no ability to stop you going to the same spot and taking your own photograph.*

But just 'cause you could-but-haven't done that, doesn;t mean you can use his without his permission.

(* although they might be able to make some claim you've copied his composition if their photograph has some remarkable enough artistic input beyond "just a picture of a city")