That presumes that the leak to Politico actually did come from him. Maybe it did, maybe it didn't -- I wouldn't take Politico's reporting at face value.
Except they didn't quote an "anonymous source," they quoted Scaramucci directly. "Scaramucci confirmed to POLITICO early Tuesday that he planned to start by dismissing assistant press secretary Michael Short at a morning meeting, but that move was apparently delayed." Link
On the record, straight from the horse's mouth. The Mooch has to remember who he talks to and what about.