The analogy doesn't work. The apple is the narrow group, while vegetables are the wide group.

To make your analogy fit to the original statement it would be: "People mostly wouldn't refer to a Honda Accord as a car". Which is the opposite of what you are saying and it's also not true, so it really doesn't make any sense.

The actual issue at hand is that there are two definitions of the word vegetable. One is the wider meaning, where all edible parts of plants are vegetables (and then apples clearly are vegetables), while there's the culinary definition of vegetables, where vegetables are savoury edible parts of plants, and under that definition apples are not vegetables.

You use the broader definition, while @Ephera@lemmy.ml is using the culinary definition.