NSFW Does having the word "porn" in the question make it not safe for work no matter what the question is about?

For example, if someone asked, “what rhymes with porn,” would that be automatically NSFW? Or something like “why is porn proliferating so widely on the internet?” Or “how can we get porn off the internet?

It disturbs me that a question about porn—a serious question, not a social question—would be considered not safe for work. It disturbs me that any question related to porn, ipso facto, should be considered not a serious question.

Where does this attitude come from? Is it part of the puerile, seventh grade boy mentality that most Americans seem to have about sex? What are people afraid of? Why do some people believe that the mere mention of porn make something not safe for work?