Well, I oppose the death penalty for serious crimes, not because I think it's inhumane, but because I think it's too good for these convicts. They should get life imprisonment with horrible food, 23 hours in a small cell, terrible treatment, brutal guards. These monsters shouldn't get a peaceful, painless, quick death. They deserve life in punishment.
However, that's another story.
My position about this is very simple.
He may have not shot anybody, but nevertheless, he's dangerous. Nobody arrrested him. He just lost his gun license, not probably the end of life for someone. People even have and carry guns without licenses, like someone proudly said earlier in this thread. There's a good reason to take precautions. For example, if someone with a gun threatens to shoot another person, would you not arrest himn? Or at least revoke his gun license? Would you wait until he shot someone that you would arrest him or revoke his gun license? There's good reasons why people suspected of supporting terrorism are arrested, and why communists in SK are arrested. They might have not committed the crime, but they have much more possibility of doing so than regular people. We must not take chances.