Why is V8 called 100 percent vegetable juice when a tomato is a fruit?
Because botanical terms and culinary terms aren’t identical. Hell, in a kitchen, even mushrooms can be considered vegetables, and they’re not even from the same Kingdom as plants.
Culinary terms have more to do with function, so if something is used as a vegetable, then it is a vegetable. If something is used as a fruit, then it is a fruit.