I had a similar experience with an open source browser extension on Google’s Chrome Store. The loudest complaints seem to be about Apple’s walled garden stores presumably because that’s where the money, but in my experience Google and even Mozilla seem to be more arbitrary in their policies/behavior. Googzilla tend to approve your app or extension and then a couple weeks later they start emailing you about various policy changes or policy updates or reviewer questions with arbitrary response deadlines such as “We will remove your extension in 7 days if you don’t send our reviewer a link to the README in your open source GitHub repo and explain again how to follow the instructions to build it. (Type ‘make build’!)
It would be nice to finish the review process before approving an app. If you have new policies apply them on the next review or ask your questions when a future update is submitted.