It seems like a lot of the negative reviews come from people who only watched one episode and barely give it a chance. Yes, this show was created in order to sell dolls, so obviously there is a focus on fashion and aesthetics. But that doesn't mean that it's shallow or lacking morals. In fact, I think this show does a better job than many other children's shows I've seen in showing how to resolve conflict, especially among friends you don't want to hurt. There is a distinct focus on teamwork and collaboration throughout the show.
I noticed a lot of the negative reviews criticize the focuses on fashion and social media. Fashion is a visual art form that people use to express themselves, and it's not inherently shallow even if that is the cultural stigma attached to it. And there is only one character obsessed with social media, the rest are not, but she receives pushback throughout the show for the times where she overstepped boundaries or ignored others' feelings because of it. And while fashion and social media feature heavily in the first episode, if you continue to watch you'll notice many of the characters are musicians, painters, actors, etc. We even get to see behind-the-scenes creative jobs like set and costume design.
Is the show flawless? No. But is it significantly better than these reviews would have you believe? Absolutely!
