It describes any edible plant

I think you meant to say "any edible part of the plant". Pretty sure the poisonous fruits of potatoes aren't vegetables.

It even refers to fruits other than tomatoes, e.g. peppers, squash, okra, corn, peas...

I already gave a few examples, you found even more. Yes, there is overlap as I said.

all fruits, some even berries

Berries in the botanical sense I guess. That does mean that all fruits are vegetables. This is like sending a photo gallery of red houses and saying "see, all houses are red"

If we wanted, right now, we could ALL just decide to start naming another subclass of vegetables, let's say roots are now called beebles

Why even make a new word up? They are called roots. And quite a number of roots are vegetables. But would you eat the root of an apple tree or of wheat? There are vegetables that are fruits and vegetables that are roots and vegetables that are leaves. Sometimes we even eat the stem or the flower. Still there are many we don't consume like leaves of tomatoes or roots of cucumber. Still others we consume in a different way. ~~You~~ Most people wouldn't consider nuts as vegetables just because other seeds are (like some of your "fruit" examples). Same with tea leaves. There are leaves that are vegetables but that doesn't make rooibos a vegetable. Same with herbs. Botanically not very different but used in a different way. The fact that zucchini is a fruit that happens to be a vegetable doesn't mean all fruits are. That's a logical error of categories I think.