But it’s from The Washington Post, a place where I expect better writing. The quote is lengthy, so I made the solecisms bold.
Carrie Dennett writes about why the Traffic Light Diet, a system of assigning the colors red, yellow and green to foods, is too simplistic, doesn’t have much impact, and can lead to nutritional deficiencies (some “red” foods have essential vitamins and minerals) and obsessive eating behaviors. Cara Rosenbloom writes about why telling people how long they will have to walk or run to work off the calories from, say, a chocolate bar, is too simplistic, can lead to nutritional deficiencies and can encourage obsessive behavior.
Simplistic already means “oversimplified.” Good writing has no such thing as “properly oversimplified” to be able to have too much of it. Use the word by itself!