(Edit: I’m posting this in GQ instead of the Game Room because it’s more a psychology question than a sports question.)
Over the years, I have encountered a number of “sports fans” who don’t seem to be fans of any particular team. Rather, their preferred method of expression seems to be denigrating the “local” team and/or its players.
Examples (I live in Washington state, so I’ll use the Seattle Mariners and Seahawks):
That guy who, upon seeing another person reading a newspaper article or listening to a news report about the Mariners, feels that he needs to contemptuously point out how much the Mariners suck. And doing this between 1995 and 2001, when the Mariners most certainly did not suck.
The sports card shop owner who, upon being asked about Ken Griffey, Jr. cards, feels the need to explain why he thinks Junior ain’t “all that” and proceeds to extoll the virtues of Wade Boggs as the superior player. (Dude, I was just asking about baseball cards.) In this case, I was a “new” baseball fan (circa 1993-94), largely unfamiliar with players who weren’t Mariners, so I wasn’t interested in arguing from my ignorance. For all I knew, Boggs was a better player. But I wasn’t asking about Boggs, I was asking about Griffey. I’m attempting to spend money in this guy’s store, yet he feels compelled to explain to me why the player whose cards I’m attempting to buy isn’t worth my time. 
The drunk woman in the bar where I was watching the Seahawks first Super Bowl appearance, who spent the entire time loudly and obnoxiously screaming about how the Seahawks suck, loudly laughing and ridiculing every time a penalty was called against the Seahawks, and generally doing everything she could to piss off the 100+ Seahawks fans in attendance. She wasn’t rooting for the Pittsburgh Steelers, she was rooting against the Seahawks. (She was eventually escorted from the premises, mostly for her own protection.)
Is there a name for that mentality?
Seriously, I don’t care if somebody likes a different team than I do, and I really don’t take issue if that fan wants to tell me why “their” team is better. That’s what a fan does. What I don’t understand is the person who just seems to hate the “local” team and its players for the sake of hating them.