My 3rd grade daughter came home from school the other day and wanted to know the difference between vegetables and fruits. I gave some garbled answer and decided to turn to the archives for wisdom. In http://www.straightdope.com/mailbag/mveggie.html , SDSTAFF Terey pretty much gave the same answer I gave my kid (or at least was trying to) but it begged the question as to why tomatoes, avocadoes, cucumbers, corn, etc., were ever called vegetables to begin with. I gave this some more thought and think a good answer (a good handwave?) is that the category vegetables includes all “savory” fruits. Not exactly precise, but think about it: if you gave the man or woman on the street a list of botanical fruits, and asked him or her to check off “sweet” or “savory” for each one, I think you’d end up with all the botanical fruits we traditionally call vegetables checked off as savory.
One of the problems with this whole discussion is the idea that the distinction between a fruit and a vegetable is an either/or question. It’s not. After all, no one asks if spinach is a leaf or a vegetable, or a carrot is a root or a vegetable, or broccoli is a flower or a vegetable. For some reason, people have a problem thinking of fruit as being in some different kind of category.
In the culinary sense, a vegetable is any herbaceous plant part typically eaten with the main part of a meal (not as a dessert). Your categorization of vegetable fruits as “savory” works, but it’s basically because of this definition, since these are the ones eaten with the main meal, rather than the sweet ones reserved for dessert.