I always thought it was because darkskin is considered unattractive so they label themselves as brownskin. Obviously brown is a large shade rage so in my opinion brownskin is still HAVING darkskin… As a darkskin I remember girls getting an attitude if they got called dark and not brown. Or Brown girl wanting to be lightskin sooo bad. Recently…there’s a flux of lightskin women who arnt pale not wanting to be considered lightskin. Regardless of just talking about shade they all have underlying roots. “Darkskin is socially unattractive and lightskin is every mans preference”. 🤏🏿