You may be surprised but that Python script you found also controls the robot via the Neato cloud You can check it yourself.

I am afraid it is the common solution for may IoT (Internet of Things) implementations. I have not seen any robot vacuums yet but I have been involved in other IoT solutions. There is nothing sinister about it, it is simply the easiest solution. The device regularly "calls home" to check if there is a new command pending. The customer uses a remote control "app" that simply makes sure the command is ready by the next time the device checks in. It is the simplest solution from the device firmware's point of view. The device does not need to know anything about its surroundings and does not require any setup that would confuse and scare away 99% of customers. All it needs to know is its own ID and the URL of the central server.

There may be a command telling the device to check in with a different server, but then you would need to implement that server yourself. There may also be a way to talk to the device locally. Try finding out the robot's IP address and then navigate to that address with your browser. It may present you a "config" page. But I doubt this could be used for a direct control. More likely for things that do not change often, like configuration or a firmware upgrade.