Moses learned an important lesson about violence and anger here. In the first case, he observed violence against a fellow Israelite and responded by killing the perpetrator. Clearly, other options were open to him: reporting the misdeed, using his position to bring the power of the state to bear against the perpetrator, advocating a change in state labor laws. In the second case, he intervened when some annoying shepherds pestered a group of young women, This time he did not kill but drove off the nuisances.
The lesson he learned was how to respond appropriately. Surely in the latter case, some force was involved (why else would the bullies retire?). Moses was getting a grip on his own temper, restraining his sense of outrage, and calculating his response to achieve just results without escalating into a vengeance situation.
That principle works just as well between states as between people. If you would reduce violence, keep your response to if firm, calm, and under control.
EXODUS 2:11-17 – 11 And it came to pass in those days, when Moses was grown, that he went out unto his brethren, and looked on their burdens: and he spied an Egyptian smiting an Hebrew, one of his brethren.
12 And he looked this way and that way, and when he saw that there was no man, he slew the Egyptian, and hid him in the sand.
13 And when he went out the second day, behold, two men of the Hebrews strove together: and he said to him that did the wrong, Wherefore smitest thou thy fellow?
14 And he said, Who made thee a prince and a judge over us? intendest thou to kill me, as thou killedst the Egyptian? And Moses feared, and said, Surely this thing is known.
15 Now when Pharaoh heard this thing, he sought to slay Moses. But Moses fled from the face of Pharaoh, and dwelt in the land of Midian: and he sat down by a well.
16 Now the priest of Midian had seven daughters: and they came and drew water, and filled the troughs to water their father’s flock.
17 And the shepherds came and drove them away: but Moses stood up and helped them, and watered their flock.