Further it is weird, that threads/Posts have been deleted - but profile pictures not.
Profile pics are much more of "personal data" (especially when it's a rl pic).
Even if not visible in public, it still has been there, which means, it must have been still somewhere in your database.
Not that I'd be personally disturbed by that, just the whole thing doesn't follow any logic.
Profile pictures have been deleted, but not necessarily at the same time as other content/info linked to an account.
I have my own account as an example of this.