Just like the people who got super angry when the author of the addon better twitch added the face...Some people got so annoyed with it that they actually blocked the word from their chat.
Oh, that's right: It's entirely possible to block certain words from your chat. Maybe if those streamers did that instead of protesting none of this would have happened.
Of course, there's always more to the story. I'm pretty sure people weren't banned for "protesting". They were probably banned for racist/sexist/threats made during said protest.