Some football fans are angry and show it in some ... sorry ... pretty silly ways.
Even if some people take offense, football can't walk away from Nike contractually, even though Nike has made some psychological and emotional distance to essentially associate itself with an important social issue. That's critical given the blowups it as seen of late, including:
Working with Kaepernick lets the company shift its own controversy to an area where it can seem like a principled winner to many. It's very slick PR in action and good for the brand. Is an of this part of a deeper conviction? Impossible to say.