It's true that the Korean standard of beauty is a girl with clear white skin. And yes, many don't consider blacks to be that pretty. But it doesn't mean they hate blacks.
If あなた are referring to the time Taeyeon supposedly 発言しました that Alicia Keys was pretty for a black person, then あなた should should know that antis translated it wrong. She actually 発言しました that black person is really pretty :)
I believe that it is absolutely not true at all. Taeyeon really didn't mean it when she 発言しました that American R&B singer Alicia Keys was pretty for a black girl. And of course Taeyeon isn't a racist at all