Fifty years ago this past Sunday, at the 16th Street Baptist Church in Birmingham, Ala., a box of dynamite placed underneath the steps exploded, carving a huge gash into the side of the building.

When the smoke subsided and the rubble was cleared, a sickening fact was uncovered. Four little black girls, in the church basement for Sunday school, had been killed. Three of them were 14 years old. One was 11.

Who killed these poor little girls? A couple of members of the Ku Klux Klan. That isn’t nearly as important, however, as whatkilled these little girls. The answer to that question is as relevant today as it was 50 years ago: racial hatred.

The hatred of other human beings because the color of their skin happens to be different, while inane, is still ingrained in the fabric of American society. This hatred dehumanizes and blinds us, making phobias, lies, and colors appear where there should be hearts and minds and souls.

Why does all this hate persist today, 50 years after the Birmingham bombing? In short, it’s complicated. Part of it is simple middle-school bullying logic. Put others down to elevate yourself.

Part of it is tribalistic, in-group out-group, us against them dynamics. Both of these explanations reveal a fact that is maddening — racial hatred is childish and immature. Its roots are inherently sophomoric, and yet, it grips our society like a boa constrictor.

This hatred has expressed itself on an institutional level over and over again in American history. It was expressed in slavery, where the color of one’s skin designated people as the property of others.

It was expressed in Jim Crow apartheid, in which skin color categorized some as second-class citizens. It was expressed in white paramilitary groups such as the KKK and the White League, which, based on people’s skin color, terrorized and intimidated them from expressing basic rights, such as equality under the law and the right to vote. It expressed itself in the bombs that ripped apart the bodies of those four little girls.

That hatred, and it’s consequences, didn’t go away when those bombs awoke a nation, complicit in evil, to try and amend its wicked legacy with the Civil Rights Act of 1964 and the Voting Rights Act of 1965. It lives on in a system of mass incarceration that holds more black men in bondage than at the height of slavery. It lives on in a criminal justice system that disproportionately arrests people of color for drug-related offenses committed at roughly the same rate as their white counterparts. It lives on in a society where people of color suffer higher rates of poverty, per capita, than whites.

It lives on in a society that portrays black and brown men as criminals and “thugs” and marginalizes and erases black and brown women from “mainstream” society. It lives on in a country where voter ID laws attempt to disenfranchise minorities under the guise of fixing the manufactured problem of “voter fraud.”

The ugly specter of racial hatred is as present in our lives as it was fifty years ago. And we, as a nation, should be ashamed of that fact because even today that hate disenfranchises, and oppresses, and demeans.

And sometimes, that hate blows four little girls away.