thats the ruling so far
so if they use it in making a video then they lose the rights to said video
Actually, it isn't. If the AI makes the creative decisions then the video is not copyrightable, just like a video made by a monkey. However, if a human uses the AI as a tool, making the final creative decisions himself, then he can copyright his work.
As long as the AI is a tool, it is no different from a typewriter. Even though you used a typewriter to write your novel, rather than writing the words by hand, it is still your novel.
Another way to think about it is to imagine that the AI is like a random number generator. The output of a random number generator is not copyrightable, but if you select the most beautiful random numbers and present them in an interesting way, you can copyright the result.