I wouldn't rule out a mistake either, since they do happen.
If I recall correctly, there was one time where Badspot accidentally made a new user an administrator when he was authorising his forum account, and he caused a bit of trouble.
But it could've been taken away for any number of reasons. Moderators aren't obliged to explain their reasons, or even give them.
And if you never report anyway, then you've not really lost anything of importance to you.