I actually wouldn't care as much if they just called her "Metal Peach." Although, I bet it's just some sort of translation error and it's going to change before release.
It does, however, bother me that they chose a recolor retexture reflection demo over some other character, like one of the DK characters, ROB, or a recurring Mario boss. Of course, the game is in development and there's probably going to be a few secret characters, and I can just play as any of the 29 other characters. Even if you hate baby/metal of characters, there's still 23 characters left.