I got a few of those rejection emails recently, and replied asking for further clarification. The replies were the exact same rejection email, but with bolded or highlighted sections. Addressing those sections got my extension into the Web Store (or at least to a new rejection email https://www.reddit.com/r/ProgrammerHumor/comments/8j5qim/pro...), so I think there is a human sending those replies, albeit with instructions not to send anything other than the rejection.