Obviously sexual desire itself is not evil or wrong. It is natural and normal to be attracted to the opposite sex and to enjoy physical contact.
There are erotic feelings which every one of us experiences. The problem of pornography is that it makes sexual desires a form of entertainment for satisfying selfish interests.
It takes those feelings that were meant to be used in a loving relationship (marriage) and excites them so that the person wants sex just for the thrill it brings. The other sad side of pornography is that those who produce it do it from the motive of the money it brings.
