“Courtesy towards opponents and eagerness to understand their view-point is the ABC of non-violence.”

This can only apply to reasonable people. The problem we have internationally doesn't involve view points that we do not understand, it involves view points that are unacceptable.

The sentiment is absolutely correct. Warren is also correct. If we stand courteous, not intervening in other state's affairs, as is the ear mark of a civilized society, with a deep understanding of our opponents, and our powder dry, self preservation stands a better chance.