I mean, it's true. Ask an American to visualize an ounce of anything other than drugs, and they probably won't be able to. Ask how many ounces in a gallon, and they'll Google it. Even cups aren't well understood. We can eyeball a mile on the interstate, or tell you how tall someone is, or lift a box and guess it's weight to within 5 pounds. But honestly, that's about it. We just aren't really taught to visualize our weights and measures, it's why newscasters keep saying shit like "8 Olympic swimming pools!" Or "the size of three football fields" because we just don't have a coherent system ingrained in us. That's also, I think, why we're so against metrification. Because weights and measures feel hard, because we're basically only semi-literate in our own mother tongue, so a "foreign language" feels like it'd be this huge undertaking.