Plagiarism is the latest weapon in the culture wars. But what even is it? - Vox

…For an academic, on the other hand, plagiarism claims are most serious when they involve stealing other people's research and ideas. For what it's worth, that's not what either Gay or Oxman have been accused of. Everyone agrees their ideas and research were original — it's their words that weren't. 

Meanwhile, there's also a widespread understanding that if you do enough nonfiction writing, you'll end up with some sort of error of attribution somewhere in your work. Ackman, who called plagiarism "very serious" when talking about the charges against Gay, seemed to change his mind after his wife was accused of similar plagiarism…

https://www.vox.com/culture/24036154/plagiarism-claudine-gay-neri-oxman-bill-ackman