@sanguish sound like just archives (if you went to back up your profile or migrate your account), not all -- pretty big difference! Strongly recommend editing your post for clarity and accuracy.
Still not great, to be fair; sounds like archives were stored public by default? (Isn't that how the Panama Papers site got breached ??) ... Is this a protocol-wide thing or just local to mastodon.social? So potential unauthorized access, but no guarantee someone guessed filenames or actually grabbed.