Because it's impossible for people to grow and learn, right?
He's still popular because his fans just don't get it, and are just as racist as he used to be. Most of the comments in the video are of white people wondering why people are so sensitive. Like, really? This isn't about hurt feelings. It's about being dehumanized, and reduced to nothing more than racist stereotypes. Some people don't get that, but Shane Dawson eventually did. I'm not saying he is completely absolved of all the things he has said and done, because unlearning problematic behavior is a never-ending process, but he's doing a lot better than most by realizing how awfully he was acting.