The Holocaust, like all massacres of an ethnic or religious minority did not start off with concentration camps and gas chambers. It started with words. It started with the dehumanization of Jews and other minorities. That led to political and social disenfranchisement, which directly led to the concentration camps and gas chambers.
After World War II, the common phrase was “never again”. Never again will we stand by as our fellow human beings are slaughtered simply for being who they are. Never again will we let a government openly persecute and slaughter our fellow citizens because they belong to a different faith or their heritage is different from ours.
Never again has become a hollow statement that often used, but rarely acted upon.
Perhaps instead of never again, we should simply say again, because ethnic cleansing has happened multiple times since 1945 and we simply continue not to care.