Because most people aren’t working 2-3 jobs for 120 hours a week. As has already been mentioned (did you read all the posts?), most people living in poverty do not work. Most people living in poverty who do work do not work full-time, year-round. As I posted elsewhere last year:
Now, many people do not work because they are disabled. That may make physical activity difficult. It does not describe everyone, obviously, but it is a consideration to be made.