It is a smart question, aptly pointed out by your answer. Whereas family and marriage have always had clear definitions, pornography can be open to interpretation.
In other words, I can provide a clear explanation for why this sort of question is a typical leftist attempt at “look at how brilliant and creative I am for coming up with this amazing question” while in fact is about equal to a low moderate sixth grade level. I’m a bit angry about the leftist influence on acceptance of pornography because this is yet another example where leftist ideology is rather dumb while masquerading as “intellectual.”
I’m not saying you necesarily take this leftist approach. But I know the influence of leftist mediocrity when I see it.
An IQ of perhaps 80 or less would not be able to distinguish between the aesthetic and the erotic. But our system of laws should not be limited to a reflection of the lowest common denominator.