Sigh.

"Dairy" has a specific meaning outside of the food groups, as does "grain." Those meanings do not shift just because someone decided to reorganize the food groups. Dairy goes in the "Protein" bucket with the new order, because dairy does have protein in it.

Also, all fruits are plants. That's not analogous to the dairy vs grain question, it would be more comparable to a "dairy vs food" debate (in which case the answer is fairly clear.)

The debate about tomatoes is whether they are a fruit or a vegetable. And the answer is that they are a fruit biologically, but they get used culinarily as a vegetable.