Please don't complain that a submission is inappropriate. If a story is spam or off-topic, flag it. Don't feed egregious comments by replying; flag them instead. If you flag, please don't also comment that you did.
Just flag spam/low-effort posts and move on with your day.
Based on Andrew's response, yes it looks like they'll be using external AI services. But since their target customer is most likely someone who uses GMail, I don't think privacy is really a heavy focus for this product.
Most PR reviews contain comments and suggestion that could easily be automated with ChatGPT, and reduce the time it takes for a PR to be merged, which makes the team more productive.