It's more complex, get some card and paper fasteners and you will see.
If both arms are the same length then the the movement of the hub will stay paralel. and the camber of the wheel will not change relative to the chassis.
But if one arm is shorter than the other you will begin to create an ARC, it may be minor and of no consequence. but the wheel camber will alter as the suspension is loaded. This is not necessarily undesirable, and may be part of the original haynes suspension design.