I have to agree - it isn't just a "gay men" issue. All one has to do to understand why so many of us, men and women, gay and straight, hate their bodies is to walk through a mall. Any clothing store actually.
Look at the Juniors rack, and at the "normal" size clothes. In the women's wear departments they are filled with all these pretty outfits, nice dresses, pleasing skirts and slacks. Men's clothing? Properly fit good looking shirts and pants in all colors and styles.
Now look at the "plus size" for women, and "big men" rack for the guys. Color disappears. Shades of grey and black dominate. Shape is non existent. A guy with a 16 inch collar and a 28" waist can get a shirt tailored to fit. One that has the same 16" neck and a thicker waistline gets something resembling a tent. Women's clothes once you get past "large" go from pretty to shapeless sacks devoid of fashion and color, or worse yet the most horrid prints. And "large" varies so widely I have occasionally held up a pair of pants and asked "extra large what? Pixie?"
Of course we hate our bodies. Who could not when just about the entire fashion industry thinks they have a right to dictate my breast size or waist size, and society in general seems to think they can put a guy down if he doesn't look like he could enter the Mr America contest in the morning? And don't get me started about shoes that are designed to cripple you! 5" spike heals and toes shaped to climb small gauge chain link fence. Honestly, who's feet are shaped to fit into those?