It was not a bad fashion statement by Michelle. It was a statement but not about fashion.
I suspect that from a purely esthetic point of view, Michelle’s dress of black and red on election night was simply some fashion designer’s attempt at “slenderizing” Michelle’s figure, at least optically at any rate. The red splashed down the front was supposed to make it appear that she was only as wide as the red strip splashed veritically and the black part of it was supposed to seem to visually disappear. Only, it didn’t work. Michelle’s a big girl, and the weird dress was a mistake that I’m sure their fans adored.