Essentially, much military training is organized bullying: the recruits are called all sorts of names, demeaned in every way, humiliated in from of their peers and every attempt to remove their individuality is made. The idea is to "tear them down so they can be rebuilt as soldiers, MuhRINES, Rangers, Seals, Legionnaires, WaffenSS or whatever.
This has been going on for centuries. It clearly does produce toughened guys who will follow pretty much any order they are given.
The only question is whether the same results can be produced WITHOUT bullying.