That's true in a taxonomical context, but it's not incorrect to call algae "plants" by other definitions. Another example: many pedants overlook that a tomato is both a fruit and a vegetable.
Yeah, the best way to put it that I've seen is that tomatoes are botanically fruits, but culinarily vegetables.
Yeah, the best way to put it that I've seen is that tomatoes are botanically fruits, but culinarily vegetables.