A constant problem is either an apathetic or even active citizenry supporting those perpetuating the butchery. They either don't see it as their problem or see a schadenfreude like glee in seeing those they deem "subhuman" or unworthy of respect being treated like scum.
Wherever you are in the world, this is almost certainly applicable to you too, it's called propaganda, and we're all subject to it to one degree or another, as well as to education that deliberately doesn't give us the tools to think critically about such things, never mind nationalist indoctrination that comes from only teaching a washed version of history, rather than an honest look at it.
This isn't to justify or excuse the actions of any state or to imply there is a power balance, because there isn't, but it is one of the many ways all states control and manipulate enough of their population to remain in control despite clearly having no value for the lives of their people, only for their own power.