In a decision that delimits the concept of race to physical characteristics that are “immutable,” a federal appeals court ruled last week that firing an employee for wearing her hair in dreadlocks is not racial discrimination.

The case centers on Chastity Jones, a black woman who accepted a job at a Mobile, Alabama, insurance claims processing company in 2010. The company, Catastrophe Management Solutions, required its employees to project “a professional and businesslike image”; Jones claims a white human resources employee told her that she’d need to get rid of her dreadlocks because they “tend to get messy.” When Jones refused to modify her hairstyle, the company rescinded her offer of employment.

Last week, the 11th U.S. Circuit Court of Appeals upheld a lower court’s dismissal of Jones’ Equal Employment Opportunity Commission lawsuit from 2013. The EEOC’s initial claim contended that Catastrophe’s actions, and all policies forbidding dreadlocks, are racially discriminatory because “dreadlocks are a manner of wearing the hair that is physiologically and culturally associated with people of African descent.” Essentially, the EEOC was arguing for a theory of race as a social construct, rather than some kind of biological classification with easily definable bounds. Race “has no biological definition,” the claim read, and besides that, “hairstyle can be a determinant of racial identity.”

The Alabama appeals court disagreed, voting 3–0 to dismiss the suit. “We recognize that the distinction between immutable and mutable characteristics of race can sometimes be a fine (and difficult) one, but it is a line that courts have drawn,” Judge Adalberto Jordan wrote in the decision. “So, for example, discrimination on the basis of black hair texture (an immutable characteristic) is prohibited by Title VII, while adverse action on the basis of black hairstyle (a mutable choice) is not.”

This decision is one setback among a series of recent victories among black women fighting to wear their hair in traditionally black hairstyles at work. Last year, a black Baltimore woman fired from Hooters for having blond streaks in her hair (it was “unnatural,” managers claimed) won $250,000 in a discrimination suit. In 2014, at the urging of female members of the Congressional Black Caucus, the U.S. military changed hairstyle regulations that forbade women from wearing the kinds of cornrows, dreadlocks, twists, and double ponytails that black troops might use to keep their hair out of their faces. The recommended styles, advocates argued, were difficult to manage for black women with natural hair. The Pentagon eventually agreed.

That’s one reason why last week’s appeals court decision is so wrongheaded. Dreadlocks don’t just have a long, deep history within black culture—they’re also directly connected to black hair texture. But focusing on physical traits while ignoring cultural signifiers of race is to misunderstand the entire construct. Nothing is permanent or absolute in race. Even the traits the court describes as “immutable” can be changed: Skin can be lightened; hair can be straightened. Theories of race as a clear-cut system of binary physical attributes have led to such dehumanizing classification measures as the paper bag test and the pencil test. Racial categories have always been subjective and culturally informed. “Professional,” “businesslike,” and “neat” are subjective, too. It’s no coincidence that traditional black hairstyles so often fall on the adverse side of those terms’ interpreted meanings. It’s discrimination.