Based on details in the letter, what do you know about kings position and the events that prompted him to wirte his letter? what claim is he supporting in this argument

This question is about  the "Letter from Birmingham Jail" written by Martin Luther King Jr.

It is an open letter in defense to their staged nonviolent resistant to racism. His reasons for staging the resistance were the following
1) He and his staff were invited to be present and support the resistance. He was a part of an organization that has an affiliate in Birmingham.
2) He is not an outsider of Birmingham because he is still a citizen of the United States of America.
3) It is his duty as a human being to stand up for what is right and protect the rights of others in times of injustice and discrimination.