I know the verse, and in my opinion, I think you are misreading--I don't think the Jesuits did me a bad turn; that would be very difficult indeed.
I never said that Jesus says that porn is healthy and its not a sin, but he says do not judge--that is clear. The verse that you mention, on the Sermon on the Mount (I can't imagine the Jesuits not teaching the Sermon on the Mount in your 8 years....) is again, like I said before, the guidelines for a Christian to live by. Yes, a married person who lusts after another woman has committed adultery, but here Jesus just defines the rules of adultery--he doesn't say we should condemn the person; indeed, his teachings both on the Sermon on the Mount and in John 8:1-11; Jesus specifically does not condemn the adulterer.
Remember what I was saying: in the Sermon on the Mount, Jesus gives a guide to Christians for their behavior. He says some things are bad--lusting in your heart after women, certainly--but he also recognizes that we are all humans, and we err and we sin. Because of that, a good Christian should not condemn or judge others for their failings, because we all have failings of our own.
Which brings us to pornography. Assuming for a moment that it is a sin, God gave us all free will, and whether or not to view pornography--and sin--is a moral choice for all of us to make; as such, Jesus tells us that we should not judge others for the moral choices that they make. If nothing else, the Gospels make that clear. Assuming, however, that viewing pornography is not a sin--because it just simply isn't sinful or Christianity is wrong--well then, no harm, no foul, and society has no legitimate interesting in banning a practice, which, in and of itself, is not socially harmful.
As for St. Paul, he is not Jesus.