I think asking people if they are "favorable" toward a sports franchise isn't the right question. You wind up registering a lot of Benign Neglect: The Washington Capitals? -- Yeah, sure I'm favorable towards them. I always want them to beat the Harlem Globetrotters. A better question would be to ask individuals to name players on each team. But polling companies hate asking questions that might display the ignorance of the people being polled.
The accompanying article "Black fans have grown to love the Redskins" is superficially dull in its recounting of things like how blacks love the Redskins because Doug Williams of the Redskins was the first black quarterback to win a Super Bowl back in the late 1980s. The article doesn't present any evidence of any NFL team that is not popular with its local black population. Americans like the NFL and African-Americans really like the NFL. Occam's Razor suggests that NFL teams tend to be popular with their local populations not because of some unique historical record but because they are local. It's not like the San Francisco 49ers are popular in San Francisco because Steve Young was an expert on Napa Valley wines or Jerry Rice was a C++ programmer. Instead, the 49ers are popular in San Francisco because they are the San Francisco 49ers. This really isn't that complicated.
But, the article is interesting in its underlying unquestioned assumption that black racialism is a virtue that should be cultivated and celebrated. The reporter didn't seem to make any attempt to find a black person to say something like, "Hey, it's great that all sorts of different people, black, white, or miscellaneous, root for the Redskins. I really like that about the Redskins: they bring us Washingtonians together."