It was just the initial adjustment. The 'automatic' part is only to keep them adjusted, and only then if you have normal wear.
You're supposed to lightly grease the contact points. Any manual says to, and I've seen dry and gouged backing plates. There's more force than from the little retainer spring. Think about it... there's so much force from the drum, even a tiny misalignment could force the shoes away from the backing plate when you hit the brakes. Bad things would happen. So they make it biased so they always get forced into the backing plate.