Well, KC isn’t the Midwest, its the Great Plains. The Midwest is generally considered the stop at the Mississippi, inclusive of the border areas.
Now the rabid fans are just football fans, KC has very weak support for a bad baseball team. No Hockey or Basketball. Can’t comment on Soccer. I imagine it seems a bit more radical when there is only one team to cheer for for a relatively short season, the fans get it all out at once. Second, unlike the vast majority of sports cities, including the Midwestern cities (Chicago, Cleveland, St Louis, Cincy, Twin Cities) the entire national identity of the city isn’t tied into sports. The cities mentioned above, especially the first three respectively, are rabid sports cities, but the culture is so diverse that it seems more tempered.
Cities where the sports fans are going to be reflected much like KC, Green Bay, and Pittsburgh are polarized. Sports are the only thing that gets these cities on the map, and therefore they are taken very seriously. This can be said of several other cities in the south and west, but the people aren’t as tied to the city as they are in the Northeast, and Midwest. To elaborate, LA, Pheonix, Miami, Jacksonville, Charlotte, and Atlanta somewhat are notoriously populated with transplants. That is to say not many families are generations deep in the cities culture. This causes a certain ambivalence to the cities institutions, sports in this case. LA is especially known for its frivalousness, and lack of cohesiveness.
In KC most people there have grown up watching the Chiefs with generations of parents and grandparents, many good memories are attached to the sports teams that can’t be attached to any other activity. In this vein, I don’t see anything wrong with the fans immersing themselves in the culture, and paraphinalia. Add to the huge amount of revenue brought into the city, and the advertisement gained everytime a game is shown nationally the support is well founded.
About the news. Your watching local news. Therein lies the answer. Local issues take top billing always, and when at any given time 10% of the city is in the stadium for the game, and 75% are likely watching it on TV. Having it as a lead in over distant world events is reasonable.
For the unbiased temperment you seem to crave, thats what CNN is for.