Yeah.... On the one hand, I don't want the government in a position to deny a fundamental civil right in the United States (to keep and bear arms), or a fundamental human right everywhere (to self defense and access to the most effective tools for it), based on a firearms competence test. It sounds like a good idea unless you know American history and remember Jim Crow and all the laws that were passed to ensure that African Americans were not able to exercise their right to vote. :/ We don't want to go down that path with gun ownership.
On the other hand, a gun in the hands of somebody who hasn't learned to use it properly is a danger to that person and the rest of us. If the person lacks good sense and good judgment, it can be a *serious* danger. While I would hesitate to back a law requiring that gun owners get training in the proper use of their firearms, I vehemently support a social norm that expects this. When I got my revolver, I was not new to guns -- I'd grown up with a father who owned guns and shot, and who taught me. Nonethless, I was out of practice and made it a point to get refresher training. I have more training scheduled for this summer and fall, training in handling a handgun in a self-defense situation.
Not all good ideas make good laws. But the law is only one way to get people to do something. Convincing them that it's right or (even better) that it's what the cool people do ;-) can be just as effective.