Not the poster, but, usually what people are referring to is all the other stuff that comes along.
Per calorie beef and broccoli are actually surprisingly similar, but broccoli comes with fiber, calcium and vitamin C, while beef comes with saturated fat.
Of course, broccoli is not very calorie dense, so you would need to eat a lot.
More realistically, tofu, which has about as much protein per calorie (and almost as much per gram) as middling lean beef. But has half the saturated fat, more iron, more calcium, and fibre.
You just get more good stuff, and less bad stuff with veg.
In terms of value meat is far more important than vegetables unless I am missing something?