How does that map onto a fictional reality?
Imagine that you have an echo and you say "Alexa, Play Rage against the machine." and Alexa does so. That is a command issued to the pilot program(Alexa) to execute a command.
The DGI Phantom 3 is a drone used in filming in our real world. It has a remote control(RCC) like most drones and A program like Alexa(pilot program) that is capable of doing things on its own. The drone only takes commands from its remote control in either case. You can move the joysticks and it moves the way you told it to. You can also tell it to follow a specific target and it does so without you having to move it via the remote control.
Johnny hacker on the other hand want to use your Drone to follow something else though. This is where spoof and control device come in. He can hack the drone(probe/brute force) to accept commands form his remote control and then move the joysticks to make the drone move the way he wishes (Control Device) but the hacker needs to have access to do so. Or, he can send it a command like "follow this other target instead" and let the drones pilot take care of the specifics but the pilot needs to think that the command is coming from its legal remote control and that is what spoof does. it issues the command to the pilot and fools it into thinking that it cam from its legal controller which is why it doesn't need access to do. You are using the legal controllers access instead.
hopefully that made sense ad didn't muddy the waters to much.