No strawman at all, but it's always fun to try to drag that out. You and others posit that Superman must be presented as "well built" (your words) because he's always been drawn that way (whether it makes sense given the internal logic of the fictional world or not). Please present some official DC literature pertaining to the metabolism thing and why Supes is muscular (and indeed how one so powerful under our yellow sun could actually become so muscular).
It's the classic fanboy double standard is all. The women (even if they're amazon warriors) must remain waif-like, whilst the men (being the male power fantasy, obv) must be "well built" and muscular.
"He's always been drawn that way!" is the best reason that can be given. Just funny is all.
Very good observation. There's no reason Superman has to be buff is there?