Your instance has data covered by GDPR, but the data it sends to other instances is covered by the same exceptions as the data you send in a email. Without exceptions for legimitate interests it would be illegal to send an email from, say, mailbox to Gmail or Yandex Mail.
So, are you saying that Facebook holds basically no data covered by GDPR?
How’d you get that from that???
Well, ok, of that list they have my ip address, but nothing else.
They accept all of that information in one way or another.
Your instance has data covered by GDPR, but the data it sends to other instances is covered by the same exceptions as the data you send in a email. Without exceptions for legimitate interests it would be illegal to send an email from, say, mailbox to Gmail or Yandex Mail.