I’ve seen so many videos of Korean people being racist toward Black and brown people simply because of their skin color, and the colorism can be really blatant. At the same time, there’s also this obsession with extremely pale skin to the point where some people practically want to look like white powder . So yeah, from what I’ve seen, colorism and the preference for very fair skin can be pretty intense in some parts of Korean society.

my guess is that they made the artist change their art style and change the ML skin colour a bit to fit in with the famous yaois since it's the most popular and loved stereotypes in korea and probably they had to fit in for money, I have seen that happen to almost every BL that gets famous and recognized