Generally Red Sox fans do not like the type of fan you're attemtping to describe....however, speaking on behalf of Sox fans, our distaste for that sort of fan is tempered by an understanding that much of their resentment for all things Yankee is a direct result of the childish and belittling treatment they've received by arrogant, egotistical, bandwagon Yankee fans.
I grew up in the New Haven area...pretty much the Mason-Dixon line between Sox and Yankee fans. My neighborhood was about 60% Sox fans/40% Yankee fans. The Yankee fans were ruthless...we were subjected to constant ball-breaking by "fans" who usually couldn't name 5 players on any seasons squad. As a result, some Sox fans have built up a serious dislike for Yankee fans.
Personally? The more I hear a Yankee fan chirp...you know, the Buckner stuff, Bucky Dent, 26 to 7, all that garbage...the more I laugh and the more it confirms that some fans just have no f***ing life, especially since their own sense of value is derived by what other men accomplish on the field of play.
So while I understand why some Sox fans really get worked up about Yankee fans and their "dominance", I agree with you, there's no reason for the bitterness if they'd just step back and realize what many of those Yankee "fans" really stand for.