Actually received a response which seems pretty straightforward. Still random and ludicrous, but that's to be expected.
• Violations:
When an item has access to user data it is mandatory to provide a privacy policy. Privacy policy URL is not provided.
• How to rectify:
Provide privacy policy URL in the designated field in the developer dashboard.
They seem to be fixated on providing an actual link to a privacy policy, which I guess needs to be hosted externally. Perhaps we should make one here? No idea why this is necessary when there's already a tab dedicated to user data policies with all the same info, or why stable was flagged but not beta. Another random act of BS, I suppose.