Come on, the penis is simply not as photogenic as the vagina. This beast of an organ lacks the classic beauty of the female "triangle." In a typical frontal shot, the viewer sees the vagina's outer panel. The penis has nowhere to hide. And some penii should remain hidden. Who desires to see a crooked, uncircumcized, hairy phallus in full swing? "Grace" does not come to mind.
I prefer the Beauty to the Beast. Keep male frontal nudity to a minimum.