Because throughout the twentieth century you welcomed an influx of people that looked white but held themselves to be superior to whites, spiritually and morally. Especially after WW2 you allowed these people, who looked white but hate whites with a burning intensity, to work against the interests of the white majority.
You let them take over institutions that shape the public mind (media and education) and determine law and justice. You allowed their philosophers’ theories to be presented as facts. You dismantled the scientific method because it’s findings clashed with their sociological theories. You allowed them unfettered access to the halls of power and an unreasonable amount of control over both sides of your politics.
You allowed them to develop a power base of social, economic, legal, moral and media control that ensures even the slightest criticism of them dooms the speaker to personal ruin. You allow them to drain your foreign aid budget to support an illegitimate state that is the source of a massive amount of Arab resentment, which exacerbated middle-east tensions to the point that the terrorists now regard you as a legitimate target. And you allow them to determine it’s perfectly all right to soak the desert sands and stony mountains of remote places with the blood of your sons and the resources of your nation.
You allow them control over your childrens’ minds and stand by passively as everyone, including whites themselves, are taught from the cradle to hate whites. You indifferently shrug as their mechanisms of control fan low embers of resentment into sheets of fire and rage. You let them amplify every grievance into an apocalypse. You let them weaponise negroid hate and callow stupidity into hundreds of millions of dollars in damage that white society pays for.
In short- you handed de facto control of the most powerful nation on earth to a bunch of people that hate you and want you dead with a nigger’s hands around your throat. And the worst part is, they have done this in every single society that has ever let them in- and you thought this time it would be different.