People work more than one job for different reasons. I work fulltime in Payroll and Human Resources, and am well compensated. However I have worked extra jobs for years, as an usher in a Theatre (not movie), and in Guest services for two local sports teams. I enjoy the second (third and fourth)jobs, plus the money helps pay for some of the extras I like to do for my kids and grandkids. I think the president is right that it is uniquely American that we can provide enough jobs for people to do this if that's what they choose. I realize many people hold extra jobs to be able to meet basic needs, but in most cases that I see it's because they are trying to better their position in life.
Given that she is a divorced mother of three including a mentally challenged child, I doubt she is working three jobs for any other reason than to support her family. Working three jobs (unless they were all part-time) would leave little time with her children.