Regardless, the human generating and publishing these images is obviously responsible to ensure they are not violating any IP property. So they might get sued by Disney. I don't get why the AI companies would be effected in any way. Disney is not suing Blender if I render an image of Mickey Mouse with it.
Though I am sure that artists might find an likely ally in Disney against the "AI"'s when they tell them about their idea of making art-styles copyright-able Being able to monopolize art styles would be indeed a dream come true for those huge corporations.
You can however disallow Google from indexing your content using robots.txt a met tag in the HTML or an HTTP header.
Or you can ask Google to remove it from their indexes.
Your content will disappear from then on.
You can't un-train what's already been trained.
You can't disallow scraping for training.
The damage is already done and it's irreversible.
It's like trying to unbomb Hiroshima.