OK, what's good about it?
Positively, pornography is obviously evil. Certainly, sodomy is evil because it's unnatural and gravely evil particularly because it's an abuse of one of man's greatest capacities, the capacity to bring life into the world.
Sexual intercourse is designed by nature and nature's God to produce offspring within marriage. Thus, a man's natural desire for a woman should be ordered toward his wife. Pornography serves to break this proper ordering of sexual desire. The logical consequences are obvious manifest in our society.
Er, no. "Unnatural" describes acts that violate the laws of nature (e.g. causing a neutral object to become positively charged without causing any other object(s) to acquire an equal negative charge). If sodomy were "unnatural", it would not happen and thus not be an issue.
Dude, are you kidding me?
"Sexual intercourse is designed by nature and nature's God to produce offspring within marriage."
I really don't think nature cares one bit about marriage. I believe sexual intercourse is designed by nature to ensure the continued existence of the species.