Why aren't private communities on PieFed federated?

Is that different for Lemmy? If so, why is PieFed's approach to private communities different from Lemmy's?

Because once it leaves the server there is no guarantee that the remote server understands or even respects the notion that it should be private.

Lemmy doesn't have private communities yet afaik.

At a guess, private piefed communities don't federate because once content federates, you can't control who can see it. All you can do is hope that the remote instance will follow the privacy settings, but you can't enforce them.

Private lemmy communities don't federate because they don't exist.

@povoq@slrpnk.net okay, yes. This is true, once it leaves the local server there are no guarantees.

However I'd have to ask whether there is an acceptable tradeoff in risk of content exposure.

After all, even in local private groups, things could get leaked via copy-paste, screenshots, etc. The weakest link is the social element.