Clothes were originally designed as ornamentation, after all, to increase your attractiveness by giving the illusion of muscle, by drawing attention to the face or crotch, and by adding color and contrast.
Here the black tie and sweater contrasts beautifully with the pale skin and reddish-blond hair. Nude, the paleness would be overwhelming.
After years of beefcake-watching, I'm quite sure what this guy is packing. It won't be impressive. But the bright-red, ribald t-shirt is a perfect counterpart to his expression of farmboy innocence.
With a sharp, severe face and sculpted physique, seeing what his penis looks like would be anticlimactic.
Keeping it hidden can be more erotic than openly displaying it. The mystery is half the fun. Hairy or smooth? Muscular or slim? Mortadella or Kielbasa?
Uniforms, symbols of status and authority, are especially flattering. This uniform accentuates the guy's chest and draws attention to his shoulders. Meanwhile his gun draws the eye downward to his rather impressive bulge.
The full post, with nude photos, is on Tales of West Hollywood.