amok: Mods are, by default, protected by copyright.
Any original work created by a human is eligible for protection, regardless of the form it takes. This includes derivative work as long as there is enough alteration, which mods typically are. Creators who want to protect their mods are legally entitled to do so and have the right to control where their work is distributed. This is a legal fact, regardless of what your personal feelings on the matter is.
BanditKeith2: They'd need to thus go through a legal process for actual copyright protection .. Which I highly doubt that many mod creator has and even then most mods use either assets from a game that's copyrighted or use imagery and brands that are copyrighted by another in such a way they'd need to go through a grueling legal process to actually prove they deserve copyright and that they aren't infringing on another's copyright
So ya maybe technically they have the right.. But they need to go through alot of legal channels that can be quite time consuming and costly .. Plus if they aren't careful can themselves get into legal trouble for the mods and such they are trying to copyright
Strictly speaking, there is no legal process for "obtaining copyright protection." You might be confusing it with patents or trademarks, which do need to be registered. Copyright is automatically granted when an original work is created / published, there is no application process required to be ‘granted’ copyright.
What does apply, however, is that it’s up to the creator to file a copyright claim if their rights have been infringed. Copyright infringement is a civil matter, not a criminal one, meaning there is no automatic legal process as there is with criminal law (e.g., murder, theft etc,). You as the creator must sue for the infringement yourself, and many people choose not to do this. However, that does not mean they don’t have copyright, it simply means they may choose not to enforce it.
