Initially, I agreed with you. But then I realized: These authors don't ever want their work anywhere near an AI. Their work could then easily be used for things they don't agree with.

Of course, if they publish it at all, it'll still be available to be used like that against their wishes, but at least they didn't support that directly.

I think Angry Robot should have a checkbox (checked by default, even) that allows the author to opt out of the AI-based classification process. That'll mean their story needs more effort from Angry Robot to review, so it's less likely they'll make it in... But if they have a good story, that won't matter.