Paul wrote in Ephesians 4:26, “Be angry, and yet sin not….” In that statement I believe Paul is legitimatizing righteous indignation. It is an anger at evil, immorality and ungodliness of every sort — an anger for that which is done against God’s purposes.
Jesus expressed holy anger (righteous indignation) at the Pharisees who resented His healing people on the Sabbath. It was righteous indignition that caused Him to drive the moneychangers from the Temple. Jesus experienced righteous indignation whenever His Father was dishonored and when others were mistreated.
As for Christians, the more holy they become the more they hate sin. A Christian should be angry with everything that takes away from the glory and majesty of God and that which is not for the good of all mankind. Holy anger is a sign of good spiritual health.