How does Dr. King respond to the idea that he is an outsider?

In the letter, King acknowledges the criticism that he is one of many “outsiders coming in” to cause trouble (their words). He explains his purpose: he is the president of the Southern Christian Leadership Conference (SCLC), based in Atlanta but operating throughout the South. He describes the extent of the organization’s reach, and then explains that one of its affiliates in Birmingham had invited the SCLC to “engage in a nonviolent direct-action program” when racial issues grew difficult there. The SCLC answered the call, and hence does Dr. King insist that “I, along with several members of my staff, am here because I was invited here” (170).