I'd say the swapping is only a symptom.

Drinker said it best in a recent video. Modern writers are, for all intents and purposes, children that do not understand basic storytelling. Or humans for that matter.

Plus: The galbrush-paradox makes it so that every conflict has to be constructed forcefully because it cannot be derived from any flaws the characters (neither protagonist nor villain) have, because portraying women and minorities as flawed is problematic.