Only if you completely ignore the preceding discussion about same-origin policies, and how browsers can’t provide a guarantee that a host at particular IP addre

Only if you completely ignore the preceding discussion about same-origin policies, and how browsers can’t provide a guarantee that a host at particular IP address is a public system or an internal-only system. A host with an IP in a private range might always be internal, but a host with an IP in a public range isn’t always external. And as the stated goal is to avoid browsers being a trampoline to attack internal equipment, not being able to guarantee that a particular host is an internal host is problematic.