Well, Factory Reset removes both /test/bin directory and /usr/sbin/ufbvncd (the VNC daemon), so it doesn't matter if anyone tries ENABLE_VNC or ENABLE_USBNET - these functions are not there for the great majority of Kindle owners. That is not to say they wouldn't be cool to have on one's Kindle.
But for everyone whose Kindle was properly reset at the factory these are just exercises in futility.