Plagiarism accusations are being wielded like weapons right now — and the multi-headed plagiarism controversy involving Claudine Gay, Bill Ackman and his wife, and Business Insider is a particularly bizarre one. It began with Gay, who stepped down from her position as Harvard’s president, ostensibly because critics found instances of (real) plagiarism in her work, but really because people didn’t like her congressional testimony on antisemitism at Harvard. Shortly thereafter, Business Insider published accusations of plagiarism against designer and former MIT professor Neri Oxman. Oxman is married to Bill Ackman, a major Harvard donor who vocally participated in a public...