How so?
Not all liars are porn users, but the porn users I know about (which, granted, is not a scientific measure) are habitual liars. It would be interesting to see a scientific study on the subject. Maybe I only know about them because their lies have gotten them into trouble.
Another thing I’ve noticed is that people who are addicted to porn often have their life divided into two personalities - the wholesome, responsible public personna and the secret bad boy personna. I think the one is the cover for the other, or the attempt to have a clean self to justify the dirty self. Which could explain why there’s such a high correlation of pastors/priests who are involved with porn.
I say these things based on statistics I’ve seen but also by observing and talking to different people who didn’t understand their own behavior and by my father-in-law’s observations as a chaplain in a maximum-security prison.
It would be fascinating to see some open-minded research on the subject.