I think the author describes it well, and makes quite clear that he is using Yascha Mounck's definition from a recent article in the Atlantic: "What people mean by “political correctness.” … [is] their day-to-day ability to express themselves: They worry that a lack of familiarity with a topic, or an unthinking word choice, could lead to serious social sanctions for them. (quotes, ellipses and brackets in original)

He then links to the full piece that contains this definition: https://www.theatlantic.com/ideas/archive/2018/10/large-majo....

To write an article about this concept, he needs some short phrase. My guess was that the issue you had with the article was not a lack of clarity, rather a lack of charity. Like "Social Justice Warrior", or "cultural Marxism", or other terms that people use predominately to refer to ideologies they disagree with, calling it "political correctness" makes it hard to to have a productive discussion with anyone who doesn't already agree. As someone who seems to take offense to the current phrase, I was hoping you might be able to suggest a less offensive alternative that would be equally clear.