well, of course. I realized that a decade ago. I've worked alongside men with less-than-svelte physiques enough to know better than to make snap judgements. I've had men in my section who couldn't begin to keep up on a run, but could carry an Iltis. You make it sound as though I were attacking someone. I had said that height and muscle are generally good, and fat is generally bad.
Gazelles are fine, but they generally don't have the body mass to hump a serious ruck. Body builders are often useless on any Ex lasting longer than a week, because they're they don't train for endurance, and they have such low bodyfat they freeze.
But, fat is not good. The human body needs a certain level to function properly, but once you get above that, it's extremely bad. Fat on your frame and fat in your arteries. Bad. Any troop that is carrying too much fat on him will always do better if he loses it. He will perform better and he will feel better.
A tall soldier has it easier because there are times when his stride can carry him through when shorter men are struggling. That's why I have so much respect for my friends who are shorter than I.
A muscular soldier has it easier because he can carry haevier rucks easier than a slight man. He can outlast gazelles at difficult tasks (trench digging, for instance), and can handle himself better in a melee.
A fat troop has to fight his own body. It wants to quit, it has no energy, it makes his already difficult task even harder.
So, height is good, muscle is good, fat is bad.