I'm also not an expert: based only on my reading of Wikipedia, you are correct and it is bonkers from a US perspective.
The photographer may be in breach of Twitter's ToS for enforcing their moral rights, but that would not _stop_ them from enforcing their rights. In this case, the initial post to twitter was not from the photographer, but someone else. So Twitter likely has nothing to hold against the photographer.
The photographer may be in breach of Twitter's ToS for enforcing their moral rights, but that would not _stop_ them from enforcing their rights. In this case, the initial post to twitter was not from the photographer, but someone else. So Twitter likely has nothing to hold against the photographer.