Thanks for taking the time to write a thoughtful reply. Here are my comments to the four points you listed:
1. Originally you said "preventable accidents", but this reply seems to shift that to "accidents", which can happen to the most safety-minded firearms users. I don't think this argument is all that persuasive, unless we're talking licensing firearms, and requiring passing a safety course. But, that's not how the 2A is worded.
2. Firearms proponents would say the odds of this happening to a responsible owner are pretty slim. The type of parent that would allow this to happen, would likely make other mistakes that could result in their children being in peril, imo.
3. I'm not sure what to say about this. It wouldn't happen to most adults, so if your concern is kids, then I would say that firearms are just a symptom of a far greater problem.
4. Yes, suicides with firearms are unfortunate. I don't think the "spur of the moment" argument will sway many, nor stand up in court.
Plus, don't most control proponents focus on handguns, and what they inaccurately describe as assault weapons? So, rifles and shotguns would not be restricted? If not, we'll still have firearm-related suicides.
If a person hates firearms, which I understand, then do what my parents would have done and remove yourself from that environment. Kids would not have the same option, so I would hope some intelligent and compassionate common sense parenting would come into play for that example.
I don't think we can ever realistically compare approaches taken by small countries like Norway and NZ with what may work in the US for similar issues. Is their per capita rate for violent crime that much lower? Probably is. What about removing just three places from US violent crime stats; Baltimore/DC, Chicago, NY. Would US stats compare more favorably to these smaller countries then? If so, we need to start in those US cities, and leave the rest of the country alone, imo.
Yes, guns are cultural. I don't think it's fair to say US culture "worships" guns. What we do worship is freedom, and firearms represent that freedom, and help to ensure our freedom. That's what the founders wanted. So you have that pesky 2nd amendment to deal with. Amend the Constitution and make firearms control efforts legal. Until then, the law is on the side of gun owners.