We hear this phrase a lot when referring to fans from MLB cities across both leagues... we hear it from players, from broadcasters, in the newspaper. It's said at one time or another when referring to fans in pretty much any MLB city.
Does it really mean something? If yes, what?
To me, it's become trite, kind of like "he knows how to play the game" and "he plays the game the right way". If you can't think of anything else to say, just pop the phrase.
Every MLB city can not have the best fans in baseball... so, do they really mean it when they say it or is it just something to say?