If you use a plain bolt the pad will only ever be parallel to it
Not so, and the types illustrated all have the bolt head flat against the am when fitted. The pivoting elements are inside the arm. V-brakes usually have spherical washers both sides of the arm and the bolt angles with the pad, but that's not what's in the pictures.
Not so, and the types illustrated all have the bolt head flat against the am when fitted. The pivoting elements are inside the arm. V-brakes usually have spherical washers both sides of the arm and the bolt angles with the pad, but that's not what's in the pictures.