He has a right to use it at his home, in public, and in his writing. He does NOT have a right to use it in the office/workplace.
Who are you to say that about a black man discussing his personal experience with racism? That is his right--and its not to be controlled, shackled or modified by those with no understanding of his plight to apply their "we know best" white liberal paternalism to his life. That is--once again--a form of control over his life, identity and freedom to express that. Those who think they know better / define offensive action/behavior/language wherr black people are concerned are almist always in no position to do so. His story was just that--his story, which is not up for control or overreaction from those in the Ivory Seat of Culturally Sanctioned Thought.
Also we have no idea who turned him in and it does not matter. Also a black person can't define what anyone else finds offensive either. That would be, to use YOUR word, arrogant as well.
Posted like one who is completey divorced from the historical, ethical, and personal right of the black American and his struggle informing his reality, including his basic right to express his experiences.