It's a pseudo-legendary in that it's like a legendary, but not a legendary. Hence the "pseudo."
I think it's stupid that pseudo-legendaries have to fit in this mold that has been created for them by the fans. It's that's sort of thing that prevents Pokemon like Volcarona from being a pseudo-legendary, which I think it should be. --- THAT'S MISS FUNERAL CAKE TO YOU love me like it's prom night