That’s partly true, but when compared to all other food groups, they typically have log orders more nutrients than even raw fruits and vegetables. The only other foods that come close are frozen entrees, but those tend to be loaded with salt. Besides, no kid is going to eat 10 servings of carrots, squash, or kale for breakfast, but they will eat one serving of cereal. I’m sure there are plenty of kids in the world who would be much healthier if they had access to breakfast cereals.
They’d get far more bio-available nutrients from a tablespoon of cod liver oil than they will from breakfast cereal, but it’s a rare parent these days who can get a kid to swallow that.
Still, a cheese&mushroom omelet with bacon is nothing to sneeze at, health-wise. (Unless you still buy into that nonsense about fat and cholesterol.)