LINCOLN, Neb. (AP) — A federal judge from Nebraska known for his candid blog posts is being criticized online for a tweet about a group of female law clerks.

Senior U.S. District Judge Richard Kopf has apologized in a blog post this week for his tweet regarding Law Clerks for Workplace Accountability, which recently formed in response to harassment reports within the federal judiciary, the Omaha World-Herald reported.

Law Clerks for Workplace Accountability, a group of eight current and former female law clerks, recently praised some parts of a June report on the judiciary’s sexual harassment policies. The group also offered suggestions, such as soliciting input from law clerks, creating a more robust reporting mechanism and making sure recommendations are applied uniformly.

Kopf referred to the group last week tweeting, “New Spanish Inquisition by SJWs (social justice warriors)? Thank goodness for Article III.” It included an illustration of a man tied to a rack. Article III of the Constitution says judges will hold office “during good behavior” and will be compensated for their services.

Kopf acknowledged the criticism he’s received about his tweet.

“I have been told by people I admire and trust that my tweet and related responses on Twitter ‘lacked nuance,’ ‘were inartful,’ or appeared to ‘punch down,’ ” Kopf wrote in his blog post. “I accept those criticisms and apologize for my errors.”

The report published last month was written by a working group of judges and judiciary officials at the request of Chief Justice John Roberts. The report found inappropriate conduct in the federal judiciary is “not pervasive” but also “not limited to a few isolated instances.” The group also wrote that of “the inappropriate behavior that does occur, incivility, disrespect, or crude behavior is more common than sexual harassment.”