Because there, she's wearing clothes that actually fit her. The cheerleader outfits were made by Hibiki years ago, which is why the skirts are so short and tight.
Which is relevant how? Besides the fact she's wearing her clothing in a way that obscures her figure, with a skirt that's fully unbuttoned and just hanging off her shoulders, we're talking about her cheerleader skin, which as I said, has always had the muffin top. Everyone has known she's chubby since that skin debuted on the JP server half a year before it was playable.
