alt Hacker NewsAI can trivially replicate average-ish and somewhat above human writing if given a tone sample to copy. Getting to replicate the quality of writing output of a decent author, probably not without a lot of effort, but the threshold here is to sound like a plausible e-mail from a book club or similar group, not to write the Great American Novel.
Categorising all the emails is not the challenge. The author needs to extract a very small number of genuine requests from the slush pile. which is a different problem, and much easier to set expectations in the community for.
I can completely understand not wanting to deal with the hassle, but pretending it's all about AI is disingenuous in my view.