I once heard someone say that there is no such thing as righteous anger, as the righteous do not get angry.
Obviously that person has not read the Bible. There very much is such a thing as righteous anger.
That does not however mean that all anger is righteous. It is legitimate to be angry at a man for beating his wife or raping his children. It is not legitimate to be angry at one's wife because she left a speck of dust on the floor.
Anger can be righteous, it can also be not righteous.
Probably the most famous example of righteous anger in all of history is Christ getting angry at the Pharisees. These people followed the Bibical law, but they did it for wrong reasons. They did it for status and social power rather than for the love of God. They took credit for their privilege and their peace of mind – both of which came from God rather than from them – while ignoring the people. There was every reason for Christ to be angry with them.
As Solomon said, there is time for everything. That also means that there is time for anger. By all means do away with non righteous anger. Do not however militate against righteous anger. If Christ got angry, then certainly righteous people get angry; and that is a reality that must be recognized.