its strange because I go to 9 Red Sox / Orioles games a year, and have (maybe sometimes only 6-7 a year) for 6 years now and not only have i never seen one fight, I have never seen a bunch of Red Sox fans taunting or berating or throwing anything at Orioles fans.
Sure there are cheers and some "sweet caroline" singing at Pickle's afterwards. Each game, however, I hear Orioles fans yelling "go the fuck back to BAHSTAN" and "Manny sucks" every single game i attend.
I suppose if by "terrible fans" you mean fans that go into another teams park and root heartily for their squad, then I guess they are, but otherwise, its a load of shit, spewed by a lot who doesnt even attend these games and/or is just pissed cause the Orioles lose all the time.
Perhaps its different in other cities but dont tell me about horrible fans, cause it's just a cop out.
now , for yankees fans, i cant speak cause the hell if i am paying money to see the Yankees win a game.