Dan Gilbert never said those words - those were Jackon's words.
If Gilbert said it, by all means, fire him.
But he didn't.
Besides, seeing Gilbert pumping his fists after the meeting with lebron, all the cavs celebrating... it looks a lot like LeBron told them he'd be back, then he booked town. Gilbert is handling this like a fool, sure, but I bet LeBron promised then skipped town.