What “ended” slavery was technology making it economically unfeasible, and the violence of it still resonates through American society today.
This is also completely false. What ended modern slavery in the western hemisphere was two tremendously violent events: The Haitian revolution lead by former black slaves, which defeated french colonialism to end slavery (and whose proclamation to end slavery was subsequently adopted by Bolivar, which sealed its end in the southern hemisphere), and the US civil war which brought an end to slavery in the US south with a bloody conflict.
Oppression has in no way ended or even been reduced as the result of violent response.
Also completely false. The biggest example is the eastern front of WW2, the bloodiest conflict in world history, where the USSR defeated Nazi expansionism and its attempt to enslave eastern europe.
I recommend you read the article I linked above, to learn how truly disgusting pacifism is as an ideology.