I'm not liking the prejudice against lightskin men on here. I lowkey already know what the reason is but I'm gonna investigate this a little further.
I think because subconsciously light skin is viewed as more "feminine" than dark skin.
Feminine can translate to self absorbed/conceit, "pretty", etc and women generally do not want a man who believes he is prettier than she is, especially if she doesn't consider herself pretty/attractive. Women don't want to compete with men. That can also dive into some deep critique on if he is gay/metrosexual. Off his looks alone.
Think of how often you see Black couples with a light skinned Black woman with a dark skinned Black man vs. a dark skinned Black woman with a light skinned Black man depicted in media/entertainment.
Dark skinned men will usually have an edge with masculinity over light skinned men and white men.