Amen. It isn't "ANGER" that is a sin, it's the "sinning" when angry that is the issue. Jesus Himself got angry. Did He SIN? No. IT was "righteous anger".
When we become angry regarding injustices, heinous evil, etc. it's "righteous anger". We are to "channel" that anger into Godly ways to alleviate that injustice, heinous evil, etc. through changing legislature, the laws, and bringing justice and eliminating that heinous evil through those channels, and through our voting, writing to our congress persons, senators, etc. and writing to the editors of newspapers, etc.
THIS is what it means to give a "voice" to and to "defend" those who cannot speak up for nor defend themselves. It's clearly written in Isaiah what we are to do. it is written that the "fast" God wants from us, is to do exactly this:
"Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? when thou seest the naked, that thou cover him; and that thou hide not thyself from thine own flesh? Then shall thy light break forth as the morning, and thine health shall spring forth speedily: and thy righteousness shall go before thee; the glory of the Lord shall be thy reward." ~Isa 58:6-8
"And if thou draw out thy soul to the hungry, and satisfy the afflicted soul; then shall thy light rise in obscurity, and thy darkness be as the noon day: And the Lord shall guide thee continually, and satisfy thy soul in drought, and make fat thy bones: and thou shalt be like a watered garden, and like a spring of water, whose waters fail not." ~Isa 58:10-11
Thank you and God bless you.