Thee are four situations in which people act violently. One is when they are trying to impose their will on others. The second is when they are defending themaselves against what they feel as attack. The third is when they are obeying orders. And the fourth is because they enjoy it.

Of course these can get confused. What seems like defensive, to me, might seem very offensive and unprovoked, to the people on the receiving end. And "orders" can be used as camouflage for "fun".