After looking through several forums and playing around with python-uinput (allows to software emulate HID stuff like joysticks) I found that this framework needs a joystick that has at least 1 button in order to use it - having 4 axes only is not sufficient!
On top of what framework was this software written? Is this Source Engine? Or UNITY Engine? I noticed that this console text output pattern ("Using libudev for joystick management") is pretty common. If you could tell me that I would open a bug report there.