Why hazing?

I do not understand the need nor use of hazing.   Never did.  As a child I read about hazing in books (Tarkington?).  Usually it was mild fraternity hi-jinks.  Still I thought it stupid and an assault on one's self-respect.
There are two instances where hazing or its equivalent is purposeful. 
The first is Basic Training for military service.  The purpose is to break down the individuality and personhood of each enlistee, resulting in people ready to accept orders without question.
The second is the initiation rite of different tribal cultures, such as the native American Indian.  These are rites overseen by a shaman and with a purpose benefitting the tribe and the individual together.
Every other version of hazing is just stupid human behavior which occasionally results in physical injury or worse, i.e., manslaughter.
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