Passage Summary: Because different groups of people have different ideas about what is polite, the author concludes that there is no such thing as a 'correct' way to behave.

Conclusion: It is nonsensical to categorize any specific behavior as objectively correct or incorrect.

Reasoning: Standards of politeness vary significantly between different cultures, which contradicts the idea of a single objective standard.

Analysis: The author is confusing 'universal' with 'correct.' Just because there isn't one single rulebook that applies to every human on Earth doesn't mean that rules don't exist within specific contexts. If a culture dictates that taking off your shoes is polite, then taking off your shoes is 'correct' in that context. The argument fails to consider that standards can be relative rather than universal. Look for an answer that points out the author's jump from 'standards vary' to 'no behavior is truly correct.'