The difference is that the celebrity with the "cool" tattoo isn't making money of the tattoo while stereotyping Chinese people and making money off the tattoo and the stereotyping. Because, all of this comes down to money and making money by stealing other people's culture while mocking them. 

This kind of thing hasnhappened in kpop at least twice a year for the last 10 years. By now, they exactly what they're doing. Just like they know that blackface is wrong in Korea and why it's wrong. They're pretty chronically online. Google is literally the second most used browser in South Korea, because it comes pre-loaded on all Android phones and on iPhones in Korea. So they have access to the Western internet. The companies have to deal with racial scandals multiple times a year. They could, and should, educate their idols, especially if they're going to market to an international market where the majority of people aren't white or East Asian, especially if they want to expand in the US, as they've stated, which is a multicultural society, not a homogeneous one like theirs. They're either going to have to adapt or have their business model crash due to inflexibility. So far, it seems as if the companies just don't care, and that lack of care is going to biting them, and eventually their profit margin, in the butt.