Civil libertarian: The categorical prohibition of any nonviolent means of expression inevitably poisons a society’s intellectual atmosphere.
Advocate's Conclusion
You're wrong. (Calling for censorship of all potentially offensive art is not harmful to society.)
Advocate's Evidence
Many people can agree on the criteria of what me mean by "potentially offensive".
Evaluate
It feels like the advocate's isn't responding at all to the concern of the first person. They're worried that since potentially offensive art is still a nonviolent means of expression, it would be "inevitably poisonous" to the society's intellectual atmosphere to do a categorical ban on offensive art.
If the advocate were at the Salem Witch trials, his argument would be the equivalent of
You'd be like,
The libertarian presumably would say,
Goal
Look for an answer characterizing a somewhat off-topic rebuttal. Our feeling that the advocate's evidence just didn't seem that relevant or compelling is probably what they're testing.