The need for war like behaviour

If one gets squeezed, one needs the ability to defend one's personal space, one's individuality. Individuality does not mean the right to boss others around. Instead it means the right to choose about one's own life as far as one does not unfairly disturb others.
Kids are bossed around by their parents and other kids plus school teachers and other adults. So they feel dearly the need to defend. So they copy from soldiers, which is just healthy as far as those soldiers have a good healthy kind of life and a good healthy kind of strategy in the society and in the world.
As adults some people have not yet found the right balance between giving in and adapting to situtions and to the needs of different arrangements and the need for personal freedom. Typically that is a result of maliciousness which makes some of their actions and intentions unacceptable and so if they stick to those, they are left with less room for themselves, so their everyday life does not go so well. If they would invest in morally ok ways to express themselves, they would not bother others so much. For example if one sits at home and eats, one is no nuisance to others. Then with stomach full can one be in a quite good mood and get along with others. Like that if one oneself takes care of one's personal needs and doies not tie them to some social tangle, it is quite easy for one to get along with othefrs and the society and find the right border between personal space and the affairs in which others need to be taken into account.
With healthy mind and spirit one is capable of defending oneself and the rights of people in a society, but generally gets along with others without needing to fight, much less to adapt to arrangements (often one's own arrangements and views)at the expence of one's personal needs or common sense to the extend that one feels malicious.