They do and they don't. Once, the only way to deal with the out group was to kill them. Slavery was developed as an alternative to killing. Now, we regard slave

They do and they don't. Once, the only way to deal with the out group was to kill them. Slavery was developed as an alternative to killing. Now, we regard slavery as an abomination. Many countries are abolishing the death penalty. There is some progress, at least for a little while.