Kate Oh was no one’s idea of a get-along-to-go-along employee.

During her five years as a lawyer for the American Civil Liberties Union, she was an unsparing critic of her superiors, known for sending long, blistering emails to human resources complaining about what she described as a hostile workplace.

She considered herself a whistle blower and advocate for other women in the office, drawing unflattering attention to an environment she said was rife with sexism, burdened by unmanageable workloads and stymied by a fear-based culture.

Then the tables turned, and Ms. Oh was the one slapped with an accusation of serious misconduct. The A.C.L.U. said her complaints about several superiors — all of whom were Black — used “racist stereotypes.” She was fired in May 2022.

The A.C.L.U. acknowledges that Ms. Oh, who is Korean American, never used any kind of racial slur. But the group says that her use of certain phrases and words demonstrated a pattern of willful anti-Black animus.

In one instance, according to court documents, she told a Black superior that she was “afraid” to talk with him. In another, she told a manager that their conversation was “chastising.” And in a meeting, she repeated a satirical phrase likening her bosses’ behavior to suffering “beatings.”