This?

In all seriousness, it's a hypothetical example. If it is something that happens, it's not going to make the news, or probably even the interweb. I'm thinking of something like the scene in Clerks where a customer at a store expresses offense at an extremely lewd conversation the employees are having, to which an employee responds, "If you think that's offensive, look at this!" and shows him the spread in the porn mag he's holding.

This kind of little thing probably does actually happen, but I agree that general objections to the existence of pornography are more common, and they fall cleanly into the other category.