Dragonite and Tyranitar are placed in between Legendaries and they are not legendary. Volcarona is not legendary. Pokemon that evolve or have a pre evo are not legendaries.
There isn't an ounce of ambiguity here. They are not Legendaries, unequivocally. Not even sure what there is to discuss about it. No one's under any obligation to explain a thing to you, particularly on a matter this cut and dry.
While I agree they aren't legendaries, I still wonder why they aren't. Your logic is that they aren't, while the OP has many arguments backing him up.
There's no debate here. They're not legendaries in any way, shape, or form. Arcanine should be considered legendary if the same logic of Volcarona being legendary applies.
If you actually read the first post, you wouldn't say that.
It can be argued that Volcarona is a PSEUDO-Legendary, Like Garchomp!
What many people are saying is that Volcarona isn't a legendary, but they're not explaining why. It's probably because GF says Volcarona isn't, but have they actually said that?
EDIT: Oops, forgot about stats. It only has a BST of around 540. Nowhere near legendary status. 580 or 600, though... too bad Larvesta evolves into it.