Without being there for the entire game I'd be hesitant to eject him. IF he had been warned for a similar event in that game, yeah, I'd be more incline to eject him. But not on the basis of events that occurred in previous games.
FWIW - my son did something similar during JV level fall league one year. It wasn't a game winning hit, but was towards the end of a game. He felt he beat the throw (was thrown out by milliseconds) and threw his helmet up in frustration. Umps did not eject him, but conferred with his coaches. He ended up sitting out the next regularly scheduled game. It was the last time he threw his helmet.
Never crossed my mind to go running to the media to "air" my grievance with the league.
Kid (and his Dad) needs to take his lumps and learn from it.