This answer is unsupported. The stimulus indicates that many people who criticize etiquette in fact believe that it is not beneficial. They may be wrong about this belief, but that's different from holding contradictory views.

This answer is unsupported. There's nothing in the stimulus to indicate that any of the people who criticize etiquette have respect for etiquette.

This answer is strongly supported. "Many" people who criticize etiquette think kindness and social harmony are beneficial. The stimulus indicates that etiquette helps people to get along, i.e. improves social harmony. This means that the critics are mistaken about the benefits of etiquette.

This answer is unsupported. We don’t know from the stimulus what, if anything, would cause the need for etiquette to decrease.

This answer is unsupported. We know that some people believe that kindness and social harmony are beneficial, but we don't know whether that belief is objectively true. Even if it were, it's also too strong to say "highly" beneficial.