The insult is in the intent. Which is why the Duke uttered that famous line. You can use pretty much an cuss word you want to describe a friend, if you smile as you say it. The same word said in earnest is likely to have an entirely different effect.
But some words get more of a benefit of the doubt than others. It seems that 'erotica', for example, is fine with most of use now. Some still prefer 'erotic [insert genre here]' but on the whole, we're good. Although 14% Are still not having it, smile or no.
Pornography however is more likely to be assumed to be an insult (57% of respondents). But a growing proportion went for some version of 'it depends'. So if the customer is using pornography as a neutral genre word they would pretty much be okay with it.
The times, they are a-changing. Shall we try this again in a year or two and see if it has shifted and in which direction?