Pod.Spec.Containers and Pod.Status.ContainerStatuses can have a different order; why?

There is a clue showing that they can have a different order and even differ in size: https://github.com/kubernetes/kubernetes/blob/v1.28.1/pkg/kubelet/kubelet.go#L2708-L2717

	for _, container := range pod.Spec.Containers {
		if len(container.Resources.Requests) == 0 {
		containerStatus, found := podutil.GetContainerStatus(pod.Status.ContainerStatuses, container.Name)
		if !found {
			klog.V(5).InfoS("ContainerStatus not found", "pod", pod.Name, "container", container.Name)

Each ContainterStatus is retrieved by Container.Name, not by the index of Container in its containing list.

I wanted to know why they are treated as unordered sets not ordered lists. I have searched the Internet spending for over an hour and failed to find any.

Does anybody know the answer?