Anger can be a good moral motivation.
(1.) Those who are good tempered are praised.
(2.) Anger is useful because it makes men keener to fight.
(3.) Anger comes in the aid of courage.
(4.) You cannot win a fight without it filling your mind; it must be treated not as a commander, but as a soldier in battle.
Anger is useful, especially in the middle state.
Anger is not a good moral motivation, because anger is not a useful emotion. If anger arises, then we are not able to control it. If it gets to the point that we cannot control it, then there is no ability to moderate it and stay a good tempered person.
You can actually control anger. Emotions are said to be beliefs or opinions. You get angry at people when you believe they have done wrong to you. Since anger is part of a belief, it follows that you can control it, because you can control your beliefs.
Emotions are feelings that cannot be controlled once it is started. Even when you or someone else you love is hurt by another person, you do not need anger to trigger the sense of protecting yourself or the ones you love from harm nor do you need anger to want to punish that individual. All you need is devotion to that person and to your own self.
Yes you need not to get angry when someone you love is hurt by another person, because it doesn't necessarily follow that you are angry when someone you love is hurt. So when you say emotions cannot be controlled, do you say there are no such things as good tempered people? Through habit, we learn to control our emotions, as the old saying goes, "Practice makes perfect."
There is no such thing as "good-tempered people" because everyone gets angry and it escalates out of their control at one point or another. In rebuttal to the saying "practice makes perfect," what is perfect? Is there such a Standard?