I forward to you the assertion that all forms of violence are symptoms of mental illness.
This definition of violence includes law enforcement, military, agricultural (animal exploitation) and religious violence, which are all normally sanctioned in most modern societies.
Coincidentally or not, this violence is almost exclusively perpetrated by human males. One is led to extract that human hormonal enhancement (or challenge) predisposes certain people to express this form of mental illness.
There are reasons to believe that in present modern societies, violence could ideally be replaced with more functional behavior, such as verbal conflict resolution strategies and diplomacy.
Violence has been rationalized as a last resort.