He let enough info slip to identify himself as a previously-banned troll. Banned people are not allowed to re-introduce themselves, so once the ID was confirmed, he was nailed.
Just a clarification - if a banned poster comes back and cleans his act up he will not be re-banned, even if his previous identity is known. It’s only when a troll comes back with a new identity and continues to act like a jerk like he did before that he will be banned as soon as his identity is established.