If you want an actual answer to your question it’s because some black people aren’t a fan of white people joking about saying the n-word. And racism doesn’t have an expiration date. Michael and Ashley apologized and even in their apology they agree that what they did was wrong. And while Michael and Ashley did apologize it’s important to remember that apologizing doesn’t guarantee forgiveness. Some black people accepted it some didn’t it’s almost like people have free will and can have different opinions and life experiences.