This is typical of the US. As soon as a work is published it is covered by copyright protection and by moral right protection (which is not in the law in the USA but in the common law of court jurisprudence).
What you are referring to here is the protection of an unpublished work by copyright that has to be of course registered somewhere.
Note you can deposit your unpublished work at the Library of Congress and that is free, as far as I know. There are many unpublished manuscripts there. They are of course protected both in their copyright and moral rights.