I watched the play during the game and in full speed, it looked like the fan was making a swipe at the bouncing ball and accidentally hit Sheffield.
Sheffield pushed him in the face with his glove and the incident was over.
The offender was arrested.
It seems to me that the incident was correctly handled. Drawing conclusions about drunken fans or players with chips on their shoulders seems out of order. Sheffield's reaction was understandable and measured. The fan is in the slammer, where he belongs.
Actually, he's not in the slammer, because he wasn't arrested at all. Nor has he lost his season tickets, or even been criticized by Red Sox management for his behavior. The only "punishment" he got was being ejected from the game. But considering the game was in the bottom of the 8th inning when he was thrown out, that's not exactly a big punishment.