David Henry Hwang's play, M. Butterfly is based on the true story of a French diplomat who carried out a 20-year affair with a Chinese opera singer, whom he later discovers to be a man. The play itself explores the stereotypes and relations between Eastern and Western culture, sexism, imperialism, and racism.
To answer your question more succinctly, Western imperialism is rife in several portions of Hwang's play. Example #1: Gallimard, who is a diplomat, insists that "The Orientals simply want to be associated with whoever shows the most strength and power.’’ He passes this belief on to American diplomats and is later excused from his post for his poor judgment. Example #2: Gallimard complains that the Chinese are arrogant, a concept he insists is common among people in Paris. Example #3: The French ambassador Toulon clearly states that he lives in China, but not with the Chinese--a thought that seems to repulse him.
These examples are just a few to illustrate the West's negative misconception of Asian culture. It is these images of a passive, demure culture that has lead the West into conflicts like the Vietnam War. Hwang's play touches on the irony of this ethnocentrism; the Western world possessed powerful weapons and technology, but this did not result in their victory over the Vietnamese. Also important, Hwang points out that the problem is not solely the West's condescending attitude toward the East, but that both sides are, as he puts it, "equally guilty" in perpetuating an imperialistic attitude of West over East.