Regardless of what copyright law states, it has no bearing on the act of photographing, or the act of possessing photos of a copyrighted thing. You cannot legally stop someone from taking pictures of a copyrighted thing if the thing is in the public view. They are two separate issues. Photographing is separate from the act of reproducing and/or distributing. Fundamental ("Constitutional") law governs the former, and copyright law governs the latter. Something must actually be reproduced – that is printed and/or distributed/published – to be in violation of a copyright; thus citing a copyright as justification to bar someone from photographing shows a misunderstanding of what a copyright actually is. You cannot go after someone for a "copyright" violation unless they have actually "copied" something. You cannot bust someone for something you think they might do; you can only bust them for something they have done.
Copyright law is on the US Constitution. A single photograph of any work may be subject to copyright. It does not require reproduction. It can be a single representation.