Imagine someone unable to read - they lose access to an important source of information. Lacking basic computer literacy is similar - they lose access to news, modern encyclopedias, research, political announcements, etc. Those resources are critical to being an educated citizen and being able to participate in the democratic process meaningfully.

An educated driver may not be able to explain in technical detail how an engine works, but they can explain the basic rules of the road and understand that a car needs oil, gas and basic maintenance. They likely have a basic understanding of what a modern combustion engine is (it takes in oil and gas to produce rotational energy) and understand that emission standards exist and that they have to follow them to some extent (they can't dump oil in their backyard).