It sounds like your implied argument is that boys do worse than girls in school because school is derived from 19th century military training. That doesn't sound right.
(I'm reading more into your comment than you actually said, I know; maybe you're just making a tangential point).
That said, one cannot fairly compare the two. The military has an express purpose of national security, and is well suited to obedience and susceptibility. Public schools, on the other hand, are little more than industrialized daycare at best, and harmful propaganda centers at worst. That and joining the military comes with benefits that extend beyond the artificial void inside a public school... it's supposed to, anyway.