I wonder what basis they think they have to claim copyright on AI weights at all, as the weights are not the result of a creative process.
Eh. A lot of creative thinking goes into creating the weights. Photography is just taking a photo, but you still own the rights to it because you clicked the button.
A lot of creative thinking goes into the curation of the training set.
Is that a battle you want to have in court against metas lawyers?
If not, then whatever they say is effectively law.