Why is the production and consumption of pornography a sin against charity?

Someone who misuses love by detaching human sexuality from the intimacy of a committed, loving relationship between two spouses and turns it
into commercial goods sins seriously. Anyone who produces, buys, or consumes pornographic materials violates human dignity and seduces others to sin. Pornography is a degenerate form of prostitution, for here too there is the suggestion that man can get “love” for money. Models and actors, producers and distributors are equally involved in this serious offense against charity and human dignity. Anyone who consumes pornographic materials, visits pornographic websites, or participates in pornographic events finds himself in the wider circle of prostitution and supports the dirty, billion-dollar business of selling sex. (YOUCAT questions 411-412)