style is only secondary. yes, the difference is iconic but basically, bara and BL is published SEPARATELY, in different magazines. (sort of like how Seventeen is different from FHM) that's the real difference.
however, there are female mangakas (BL mangakas) that can do muscle-y style and they are called "gacchiri" something like the style of fujisaki kou and sakira
Can something be Yaoi and Bara at the same time? Aren't they very different styles (even if both are about gay sex?)