(As a result of that #pixelfed issue washed up yesterday, it seems just like that: Don't rely on "privacy" settings anywhere in the ActivityPub world. Use other tools for that, ideally dedicated messengers. Or use networks such as Hubzilla or maybe Friendica without AP. As of now, maybe best to do is just consider everything at least in the ActivityPub part of this world to be public, world-readable, world-crawlable, ... communication. There apparently are no really private profiles or posts.)