This, I think I look hideous and I'm not sure what my gf sees in me! I mean I'm relatively thin and fit, but I just don't understand how anyone could be attracted to the male form. It's just not hot to me, so I don't know how to make it look pretty in pictures.
I think a better question is "what do the nudes you like look like?"
Like, if you're a straight male you're never going to be turned on by your own nudes but I know for the majority of straight men they aren't looking at just closeups of vaginas or boobs. Translate that to the male body.
I don't think that's it; I'm gay and get nudes from other gay guys. Results are still consistent with the OP's example. I think girls consider the whole body aesthetic more, guys are laser focused on "here is a close-up of my dick", "here is my asshole", "so we ready to go, or?"