Body builder is mostly a power lifter who periodically calorie-restricts to get a lower body fat percentage (there are differences in program design, but "in general", thats the major diff). Easier to gain muscle strength when you're not diet restricted, so power lifters always get stronger than the builders over time and people mostly pay attention to the people with the most experience.
Note that the classic power law makes its appearance once again. True, the bell curves for lifters and builders have little overlap and most of the not-as-thin lifters will be much stronger than most of the thin builders. However, most of the time they are competing with the general population not with each other. Both experienced body builders and power lifters are significantly stronger than, perhaps, 99% of the male population, which honestly is not a very high bar to exceed.
So due to power law effects when competing against 99% of men, the primary correlation with winning is strength. Yet when competing at the top of the pyramid, against other men in the top 1%, you are also correct that lower body fat percentage correlates with winning, because everyone "up there" is already pretty muscular to begin with. "The football team is the strongest and most successful group, but the individual on the football team whom is the most successful has the lowest body fat percentage inside his group".
Note that the classic power law makes its appearance once again. True, the bell curves for lifters and builders have little overlap and most of the not-as-thin lifters will be much stronger than most of the thin builders. However, most of the time they are competing with the general population not with each other. Both experienced body builders and power lifters are significantly stronger than, perhaps, 99% of the male population, which honestly is not a very high bar to exceed.
So due to power law effects when competing against 99% of men, the primary correlation with winning is strength. Yet when competing at the top of the pyramid, against other men in the top 1%, you are also correct that lower body fat percentage correlates with winning, because everyone "up there" is already pretty muscular to begin with. "The football team is the strongest and most successful group, but the individual on the football team whom is the most successful has the lowest body fat percentage inside his group".