How would what you claim be true by analogy, in math for example? (2+2=4)
2 and only 2, plus 2 and only 2, equals 4 and only 4, doesn't that mean that 4 and only 4, minus 2 and only 2, equals only 2?
If 2 is sex and 4 is porn; how is your view consistent?
Simply watching sex can be a form of sex being depicted in real life or digitally. In my view, live sex can be a form of porn, especially if I am not present in the audience, or participating. Therefore, sex and porn are indistinguishable in normal circumstances.