It is weird that He Man is the only MotU character other than She-Ra to get a pronoun in their name. But then that would get us to combinations like He-Beast-Man, He-Ram-Man and He-Man-at-Arms. So I guess that means that He-Man, as the most generic name, is the audience stand in.
It’s even weirder given MotU naming conventions that Man-at-Arms doesn’t have, like, a batch of arms.
Addendum, while on the pot I realized that technically “They-Men” would accurately refer to more than one He-Man, for example if you had multiple action figures to reflect different eras of manufacture or Laser Power He-Man, Anti-Eternia He-Man, and regular Very Gay He-Man.