I don't buy the GP argument at all. But you have to take into consideration that most code is similar. All the code in a project when put together may be unique

I don't buy the GP argument at all. But you have to take into consideration that most code is similar. All the code in a project when put together may be unique but snippets of code in one project - which is what presumably chatgpt is giving you - is not all that unique. Claiming ownership over that is somewhat meaningless.