why would Overeem care if some little idiot tries to clown him? The only people that get flustered by someone pulling this kind of stunt are those with fragile egos that need reinforcement all the time.
Overeem handled it fine, didn't get angry and laughed it off and only even really noticed it at the end then just went along to get him to shut up. This wasn't a gerry dee kind of joke, that guy was trying to inflate his own ego by pushing around a HW. If it was a setup act Overeem would have acted angrily, it was a case of desperate ego versus confident fighter.