When we go surf on the net we have a link established between virtuality and reality, a real human use several interfaces to access a virtual space.
When a hacker is breaking into a system, he is doing so at light speed, trough optic fibers, remotely, sometimes tousand kilometers from the physical computer he attack. If the law of the real world want to counter attack him, it cannot be done at the same speed, and distance abstraction, since the virtual world cannot influence a human directly. So we have to run a hunt in the physical world. Problem, the physical world is nowhere near as fast and flexible. A hacker could literally hop from place to place without ever being caught.