The AI is not intelligent. That doesn't matter.
Nothing anyone owns is being copied or redistributed. The creator isn't the tool; it's the person using the tool.
AI needs two things to work, an algorithm and data. If training is allowed to anyone, anyone can create their own algorithms and use the AI as a tool to create innovative new messages with some ideas borrowed from other work.
If data is proprietary, they cannot. But Disney still can. They'll just as successfully flood out all the artists who can't use AI because they don't have a data set, but now they and the two other companies in the world who own IP are basically a monopoly (or tri- or whatever) and everyone else is screwed.