While all of you make valid points, I still think it's being over-analyzed. The fact remains that it's just not "cool" to be a Sox fan in Chicago, and it's "cool" to be a Cubs fan. That's what's emphasized all over Chicago media, Wrigley Field and the Cubs. It's a shrine, the Cubs are a "storied franchise." The "long-suffering Cubs fan" has become part of Chicago lore, and are held up as some kind of example for all sports fans to emulate. "Oh, they're so loyal and passionate about the Cubbies!"
The news people fawn over the Cubs when they hand off to the sports guy on the 10:00 news. Anything negative about Wrigley or the area around it is not talked about; it's all sunshine and unicorns.
"Nellie Fox, that little son of a gun, was always on base and was a great hit-and-run man. He sprayed hits all over."
Yogi Berra in the New York Sunday News (July 12, 1970)