A middle school teacher’s casual use of the idiom “pot calling the kettle black” took an unexpected turn when her 6th-grade class reacted in horror, assuming the phrase was racist. Kids have never heard the phrase before"Yesterday, a girl called out a student for not minding his business," wrote u/ascaffo. I quickly quipped, isn't that the pot calling the kettle black? What is the origin of the phrase, "pot calling the kettle black"? The pot calls the kettle black because the kettle is covered in soot.