Chesterton explains how Thomas Aquinas was way ahead of his time in understanding what it means to be human and had a developed a great sense for ontology. He would argue that there are many of his own contemporaries that think and develop their ideas just like Aquinas did. You can use this as a starting point and develop your essay.
The examples has to do with his people trying to raise their own point of view when a misundertanding raised to the point of altering their unity. Tutu was right to be fair to both sides in order to be impartial and to raise only onw point of view to remain united