The illustrated directive is unclear. Drone, also known as unmanned aerial vehicle, has different form factors. If the sign comes without the icon, then it’s pretty clear. With the icon there, it becomes only this type of drone is not allowed.
This happens exactly in typical policy statement for network connection where cybersecurity practitioners have implicit assumptions. The issue has been elaborated in earlier blog for network connection.
In nutshell, the precise directive is to secure the network with the appropriate controls of layer 3 to layer 7 data flow.