Thanks for the question! The wording of this one is definitely a bit confusing.
The critic concludes that it is unsurprising that comedians who are disrespectful in their acts are currently popular.
Why? The critic tells us that people currently value respect. However, the critic also tells us that people failing to live up to ideals and exaggerating said failures can lead to good comedy.
Answer choice (A) is incorrect because it would weaken the critic's argument. If the people who enjoy such comedians do not value respect, then it would still be unsurprising that such comedians are popular, but not for the reasons that the critic posits.
Answer choice (D) on the other hand is a necessary assumption for the conclusion to be properly drawn. If we negate this answer choice, then people who value respect would always succeed in respecting others. If this were true, then there would be little to no successful comedy because there would be no failures for comedians to exaggerate.
In other words, in order to properly draw the conclusion that the popularity of comedians is unsurprising because of the comedic effect of exaggerating failure, we must assume that people do not always succeed in being respectful to others.
Hope this is helpful! Please let us know if you have any further questions.