Digital media platforms like Google and Facebook may disavow responsibility for the results of their algorithms, but they can have tremendous — and disturbing — social effects. Racist and sexist bias, misinformation, and profiling are frequently unnoticed byproducts of those algorithms. And unlike public institutions (like the library), Google and Facebook have no transparent curation process by which the public can judge the credibility or legitimacy of the information they propagate.

That misinformation can be debilitating for a democracy — and in some instances deadly for its citizens. Such was the case with the 2015 killings of nine African-American worshipers at Emanuel A.M.E. Church in Charleston, S.C., who were victims of a vicious hate crime. In a manifesto, the convicted gunman, Dylann Roof, wrote that his radicalization on race began following the shooting death of Trayvon Martin, an African-American teen, and the acquittal of his killer, George Zimmerman. Roof typed “black on White crime” in a Google search; he says the results confirmed (a patently false notion) that black violence on white Americans is a crisis. His source? The Council of Conservative Citizens, an organization that the Southern Poverty Law Center describes as “unrepentantly racist.” As Roof himself writes of his race education via Google, “I have never been the same since that day.”

Roof’s Google search results did not lead him to an authoritative source of violent-crime statistics. FBI statistics show that most violence against white Americans is committed by other white Americans, and that most violence against African-Americans is committed by other African-Americans. His search did not lead him to any experts on race from the fields of African-American studies or ethnic studies at universities, nor to libraries, books, or articles about the history of race in the United States and the invention of racist myths in the service of white supremacy. Instead it delivered him misinformation, disinformation, and outright lies that bolstered his already racist outlook and violent antiblack tendencies.Online search can oversimplify complex phenomena. The results, ranked by algorithms treated as trade secrets by Google, are divorced from context and lack guidance on their veracity or reliability. Search results feign impartiality and objectivity, even as they fail to provide essential information and knowledge we need: knowledge traditionally acquired through teachers, professors, books, history, and experience.

It’s impossible to know the specifics of what influences the design of proprietary algorithms, other than that human beings are designing them, that profit models are driving them, and that they are not up for public discussion. It’s time we hold these platforms accountable and perhaps even imagine alternatives — such as regulation of search engines — that uphold the public interest.