The concept of intersectionality, which they mangle, is not about a weird race to the bottom contest of 'who is more oppressed.' It's just being aware of how intersections of oppression affect people. For instance, if you're white and gay, your experience will be different from someone who is black and gay, because they deal with racism and homophobia and not just homophobia. Or if you're physically disabled and poor, you have to deal with navigating the world both as a poor person and a physically disabled person, whereas an able-bodied poor person doesn't have to worry, for instance, about gaining physical access to shelters, about free or low cost health clinics being able to treat their disability, etc. It's a really useful concept to consider when developing policy, setting up events, etc. but it seems that all fats use the concept for is to try to jockey for a place as the MOST oppressed. But fatness is entirely within their control!