You are right, I should have been more precise.
I do not believe that it's a civilian's job to enforce laws. I do think that defending yourself against a criminal with violence should be the least of all options. The best thing you can do is 1. run away 2. call the police 3. stay out savely.
When those options are not available to you you may fight back, but to do that you do not need a loaded gun, you can use tools that you can improvise with other tools you can find around your house (yes, I realize that that sounds somewhat ignorant, but considering the potential dangers of owning a gun it seems more ignorant to me to arm people who never received proper training).
Guns have the potential to help both the criminals and the victims, leading to a vicious circle.
Therefore I am in favour of a prohibition if that can be enforced, as stated in my first post.