War is a major part of American history. From civil war, to foreign wars, they all have been fought. The reason these wars were ever started was out of anger. However, don't think about it in a negative way. A prime example is the civil war. This was the fight for freedom. Can you honestly say that wanting freedom would not make you angry? I believe that it would make most people angry. What was the outcome of this anger? A war between the north and the south. The fight for slavery, saying anger is of no use can be compared to saying African Americans should still be slaves. If anger is of no use we would have never fought back to slavery. Anger is meant to be used as a good moral motivator.
The civil war was not done out of anger but rather for what was morally right. The forefathers of the United States had declared in the Declaration of Independence that slavery would be abolished. But that was taken out because not everyone would have agreed to it. The United States was more focus on getting their freedom from Great Britain. So the civil war was not done out of anger because this was a problem that was suppose to be dwelt with when the American Revolution happened.
So just to be clear, you are stating that slaves were not angry to be slaves. If they were not angry that would mean they are contempt as slaves and have no reason to fight back. Therefore, the civil war would have never happened in the first place. How would a slave know what's morally right? Their whole life is brought up on a plantation where there taught to be a slave, not how to treat people. They felt angry about the way they were being treated. Their were other people who felt angry about how they were being treated, this is what caused the war to get rid of slavery. Anger pushed them and the north won the war.
Slavery didn't actually anger most slaves. Some slaves were actually happy being slaves. Those are the ones that were taken care of and not mistreated. They were given the basic needs to survive: food, water, and shelter. The civil war mainly happened because Abraham Lincoln wanted the country to be a whole after the South had seceded, not actually for slavery.
Okay let's say slavery didn't cause a lot of slaves to actually be angry. I would like to know how you would being a slave and sold like a piece of meat? Would you be happy, just because you had food and shelter. I' don't believe that's enough to keep a person from not being angry. I believe that any person being treated like an animal would be angry, and use that emotion to change that.
The problem of the slaves being "angry" is that we don't know how their life back home actually was. Maybe they preferred being slaves because those basic needs weren't being met in their homeland. But most people would be happy being alive regardless of the circumstances they are living in.