"In this case, it's sexual sin. Sex is intended to create a lifetime bond between a man and a woman."
Well, that's one way to look at it, I guess. Still, sex is common to all mammals. All of us mammals have the same parts, and sex is done pretty much the same way.
I don't believe in any special status for humans among the mammalia. Sex is for reproduction of the species, and it all works pretty well, overall.
Human beings are, perhaps, unique in that they have the power of imagination. Because of this, human males have always created images of human females as a stimulant for the imagination.
You call Hefner's depictions of women pornography. I can't see that definition applying to the idealized, airbrushed women depicted in Playboy. I'm old enough to remember seeing the very first issue of Playboy as a youngster. I was bemused by it, of course, and I believe I did a naughty thing after seeing it.
However, it was not the first photo of a naked woman I had seen in my youth. Not by a long shot. There were lots of photos of naked women out there. They weren't as well-printed, of course, but who cared, really?
I stopped looking at Playboy when I was about 16. By then, I had opportunities to view the real thing, and found it far superior to those Playboy photos. In short, I got on with my life.
Playboy is not, and never has been, pornography. It's very far from pornography. I've seen pornography, and it's quite a different thing from those soft-focus photos in Playboy. Those are just nude women. Pornography is something else again.
Your tagline suggests that your worldview and reality don't match. Of course, you will believe the same thing about those like me who believe in G-d and what He says. Time will tell.
Before you enjoy your intellectual superiority, tell me about the strip clubs dogs or chimpanzees create.
Shalom.