Also think about Chaldea's situation, they're completely cut off from the rest of the incinerated world. There's prob not new porn being made, so whatever's in Chaldea or his own drives might be all that's left.
Gudao has a collection of servant half of whom are female and at least a quarter of the female loves him. Not to mention at least a dozen would not hesitate at all to have sex with him.......... Yet he still masturbate to porn???