Re-read paragraphs 27-30. How does King respond to being labeled an "extremist," and how does his use of the word "extremist" contribute to the tone of the text

An extremist is a person who holds extreme or fanatical political or religious views, especially one who resorts to or advocates extreme action.

He might react negatively to it, setting an uncomfortable tone.

I don't know what your reading so it may be inaccurate.