I have to disagree with you there. Boys and men (who are not TG) have no wish to present in any way, shape or form as feminine. It is not who they are. And it also doesn't mean they are into muscle building.
I can think of scores of males who are not into the stereotypical guy stuff: the musicians, the artists, the history buffs, the political activists, the scholar bowl guys who have their own brand of sexiness in high school for some girls, by just being brainy, or intensely into whatever it is they're into even if it is not muscle, guns, and cars.