The judge is dumb because I, an idiot, can not read anywhere in the U.S. Constitution where it says the Second Amendment was written with self-defense in mind.
It literally only says that everyone can own a firearm because a militia (an organization that exists outside of the military or law enforcement institutions, but answers to a state governor) is necessary to maintain a free country protected from any threats to the country.
And a militia can't exist without regular people being able to own guns, so they can train with them, hence where it says "well regulated militia": meaning in good working order. You can't have a militia in good working order without being able to train with your firearm.