What is the author's tone in No Future Without Forgiveness by Desmond Tutu?

Desmond Tutu has a unique personality that combines compassion, justice, love and mercy for all of humanity. He also reveals impatience with those who accommodate or commit injustice that gives his tone a certain peskiness. Tutu also has a well-developed and almost child-like sense of humor that is deeply theological and often concerns the absurdity and arbitrariness of injustice and racism.