I don't think it's really dark skinned women but dark skinned men who shame dark skinned women for being dark and praising lighter skinned women and non black women. Dark skinned men will make a joke or shyt on a dark skinned woman before anyone else. That is traumatic for many dark skinned women who may channel that hurt and pain towards the world. A man the same skin tone as you telling you that you are ugly and making you the butt of jokes is strange.