Another social institution where soldiers are made to dig trenches from dawn till dusk, and are also taught how to wash and mend clothes, clean the territory and premises, peel tubers, learn basic hand-to-hand combat, physical education, subordination, and other things that not every hardcore student can do on their own.
Of course, in the army, as in prison, the collective is strict, and if you are being dunked in the toilet or punched in the liver more often than others, then it's for a reason.
And in general, why are you so sure that it's justified? In school, (people like you) beat the weak just because they are weak. Is that justified? Ugh, disgusting.