People who feel hurt or victimized by any kind of experience have a tendency to be consumed with anger. This is natural at first, and we empathize with such feelings.
Also, there IS such a thing as righteous indignation. (Of course, most people think that's what they have when they are angry: righteous indignation.)
But, USUALLY, when people are angry, they are involved in something lower in both tone and motivation than anything that could be described as truly -- or perfectly -- righteous. Generally, far from being truly righteous, the anger response is quite low -- right down there with hatred and violence.
The pro-anger school of psychological thought, as well-meaning and well-reasoned as it may be, is, by promoting anger, promoting the heroin of the soul -- something that is both terribly addictive, and fiercely destructive. While anger may have some usefulness in relieving a tendency toward excessive guilt, in the case of people with strong ethical sensibilities based on their natural spiritual leanings, excessive anger only increases guilt. And, as an extended experience, anger is debilitating, and can render any person dysfunctional.
If it is peace that you want, give up anger altogether. Walk away, even, from negativity and negative views. This walking away is NOT about denial. Quite the opposite: it is about ACKNOWLEDGING the truth. It acknowledges that excessive negativity is spiritually, emotionally, and psychologically ruinous. It admits the fact that indulging in anger will rob you of all your peace in a second -- and leave you peaceless for a long time thereafter.
Of course, getting rid of anger takes time. But more than time, it takes real commitment. Your anger reactions WILL wind down if unfed, just like a stray dog that doesn't get a bone. When you have succeeded in not PRESENTLY feeding the patterns of thinking that you learned in the past and continue to justify based on the past, the past will no longer bind you in the present.