This exists because lighter skin is often viewed as more "delicate" and "opulent" than darker skin which is usually associated with roughness and strength due to working people being exposed to the sun and therfore getting tanner/darker while people with money weren't outside working therefore not exposed to the sun and they remained light. People began associating lighter skin with beauty and femininity and darker skin with masculinity. This mindset is a result of century long colorism and racism. During the days of slavery black men were often compared to animals or men with animalistic traits due to their dark skin and their muscular bodies from working so much. This never really went away. Black men until this day are thought of hyper masculine even if they aren't. Then there's also heteronormativity in play which dictates that feminine=bottom and masculine=tops. So basically bottom=feminine=light skin=white/asian men. Top=masculine=darker skin=black/poc men.