Probably about the same time they decided to change from “liberals” to “progressives” because liberal had such a bad taste in Americans’ mouths. All their media dutifully made that change as well.
Kinda like flip-flopping the red state and blue state designations, because Democrat = Red State = Communism, so “let’s call us the Blue States and the Republicans the Red Staters,” decided on and led by the media, I believe.