During the time the guys were talking, they brought up the different viewpoints from the girls and from the guys. One of the guys said that they wanted to know how the girls feel when they see the bodies of the opposite-sex. They touched on a lot of the same things like the statue observation, the eye contact, poses, etc..
One of the things that surprised me was the fact when the the guys said they would've had different discussions if the girls weren't in the room.
Overall, what i took from these discussions is the fact that beauty is expressed in different ways, and in this case, they show "beauty" one way or another. i mean some of those pictures were just disturbing, but for most, i could see the emphasis on the "beautiful" that people don't usually see as beautiful. I mean, I don't think that all people think a naked man in a field is the most beautiful thing on earth, but, for example, the track girl with one fake leg is expressing her athletic beauty. Having all of these people naked i think just emphasizes the beauty of the body, not a brand or anything else, just the body itself.
The reason, i would say, they use athletes' bodies is because that's the bodies we want to see, those are the bodies we admire.