Jon, guns have been very regulated in NZ for a long long time, so it's understandable that you don't understand why some countries allow more lax gun ownership and gun use laws.
We grew up with guns around. Almost every house has em......... except Democrats as one of the charts below shows.
http://www.pewsocialtrends.org/2017/06/22/the-demographics-of-gun-ownership/
I don't know the 'lay of the land' in NZ as far as property size, distance from home to home, how many percent of the people live in the city and how many percent live in rural areas, spread out like say ranches or farms or people who simply live away from populated areas.
Where I live, it's small cities, 17 to 27 miles apart up and down the entire coast with forested areas in between. A lot of people live outside the city boundaries so they don't necessarily have a neighbor's house 25 or 50 feet away. So we aren't tightly packed together. This describes a huge part of the US population. We grew up being able to go out in the back yard and 'plink' with a .22 as target practice like shooting the flowers off of distant weeds, or knock a small cone off out of a tree. It's a lot of fun testing your skill level. From there it was pigeon hunting, or duck hunting, deer hunting. It was as common as apple pie......... just normal to us.
City folk..... people who have lived in the cities most of their lives certainly have different experiences and viewpoints, but for smaller communities and rural communities, gun ownership is often a right of passage. A single shot bolt action rifle has been passed from relative to relative as members of our family had children that became of "teaching age"......7 or 8 years of age. I'm talking an age to instill gun safety and under adult supervision. You don't give a 6 year old a gun to play with at age 7 unless you're Rusty.
We don't have a gun problem, we have a social problem with too many people having no value for human life, respect for other peoples property. Drugs are a problem, single parent households are a problem and a lot of others.
As a kid, TV programs drummed into our minds, respecting parents, looking up to TV idols like super-heros, TV westerns and such. In TV sitcoms of old, kids always addressed or replied to their father or a policeman saying things such as "yes, sir"
...little kids today grow up watching TV with total disrespect of their elders and of police. I think that's a big deal and hard or impossible to correct once a kid gets past a certain age. I'll blame 90% of our problems on the media...... they don't teach kids "the good stuff" anymore.