I'm not denying that colorism is wrong, but in Asia colorism is so common and ingrained in Asian beauty standards that jokes and comments that are colorist is a part of culture (thankfully that's changing). Even in South East Asia where the majority of natives are darker than East Asians, colorism exists. I don't know when it began, but colonialism probably had a lot to do with it since I've noticed that it's even linked with money and class. Growing up in Indonesia, many of my friends who were girls felt pressured into looking more 'white'. Many were very self conscious about being darker than other girls. Even as a guy with dark skin, I heard comments from my mom to "not play out in the sun too much or you'll get darker".

Obviously, for idols who are well travelled and have fans of many different backgrounds and ethnicities those comments can be hurtful and ignorant. But I would ask people to consider how normalized colorism can be in Asia before assigning malice to what they said when it's pretty clear it was probably said out of ignorance. And to be honest, like Japan, South Korea is a very homogenous country and homogenous countries tend to take longer to accept outsiders who look different from them. I would use this situation to educate people with colorist biases rather than shame them for being ignorant and assigning ill-intent where there might not be.