1. Michelle is not the ugliest woman ever to have lived, not while Helen Thomas is around, but she's so far from being one of the hottest one hundred (or one billion) women in the world that this is obviously a lame political gift or subtle satire.
2. There have been a very small number of First Ladies who could be called "hot", but most have been women with dignity who have chosen to look and act their age instead of trying to be something that is difficult or impossible for most women of that age. 
... although Jackie was pretty cute.