I used to think this sort of fan was some kind of strange Steelers phenomenon, but I've found out going to scifi conventions that this particular type of fan crosses "fandoms," be it sports or science fiction or whatever.
Basically, with this type of fan, no one can hate the object of their fan obsession the way they do. They hate every last decision, possibly because they envy the people involved and wish it was them making starting lineup decisions, or play decisions (or in scifi--story or casting decisions). But god help you if you talk about about the object of their obsession. The Steelers could have given the store away, and they may be bitching a blue streak, but if YOU complain, and you're not a Steelers fan, you're probably about to be set on fire.
Tell a Star Trek fan that you hate Star Trek, and you don't get what the fuss is... oh yeah, AND you REALLY hate the new movie most of all. Same deal. They'll go off for 40 minutes on the virtues of the new movie, even though they were just trashing it 5 minutes ago. Same deal as Super Fan.
I suppose we should be thankful they're turning their propensity toward fanaticism toward sports or science fiction (or WHATEVER) and not toward... something more serious. Then they'd be even MORE freakin' unbearable.