An unskilled driver is a danger to others, potentially even life-threatening. The worst an unskilled computer user can do is inadvertantly pass around a virus. I don't think it's a fair comparison.
Perhaps in the worst case, yeah. But, I think this is a situation where it is more useful to look at the average case rather than the worst case. In the average case, an unskilled driver is a huge pain in the ass for everybody. The same goes for an unskilled computer user. Unskilled computer users are the reason that many viruses are able to spread as far as they can. Unskilled computer users force designers to dumb down interfaces making it harder for skilled users to do what they need. Unskilled users do create a lot of problems that wouldn't exist if the unskilled set had even the slightest bit of clue.
I agree that "Computer Licenses" (and I think that we're really talking about "Internet Licenses" rather than "Computer Licencing" here. A computer not connected to the internet does no more harm than a car that isn't turned on.) are definitely not the answer, but you can't ignore that unskilled computer users are a problem.