As the quote says "Not all but some of these foods tend to be low in fiber and nutrients". Chips are given as an example of that as are sugary drinks, cookies, some crackers, breakfast cereals, some frozen dinners, and luncheon meats. Further, "These foods may partially if not completely replace minimally processed foods in some people’s diets".

Chips in particular are cooked in low-quality oils and highly salted (a pack of crisps in my neck of the woods has about 1.5 to 2% salt). Of course you can do that at home and nobody's stopping you, but chips are sold by the million tons all over the world. Hence the concerns about making peoples' diets a mess.