You were lied to in the sense that all "superfoods" are just bs marketing to sell you the latest cook book.
Spinach, kale and broccoli is good for you, but any argument for why these are good and not apples, seeds, beetroot, carrots, yams, potatoes, pineapple, bananas or whatever is entirely subjective.
That or its "chock full of antioxidants" or vitamins or iron or whatever the fuck quality it is they decide on, which they can market the latest crop that had a particularly good harvest season