Amazon allows public domain, but they have restrictions. They require at least 25% new work, which means even if the "AI" created stuff was public domain, it would have to have more stuff added, like commentary, illustrations and so on to comply with the rules.
I really don't see how anyone is going to get this stuff published. You can't claim the copyright on it, no matter how much you do to it (and most of this stuff? Nothing was done, it was uploaded as is).
One thing for sure, Amazon, et. al., needs to settle down and make some firm rules on how this is going to go. They also need to figure out how they're going to explain to their customers how this stuff is coming up on searches, most of it's very bad, and customers have already shown their disfavor.
In the meantime, expect upload times to get longer, searches to get worse, and readers to get angry.