I'll tell you the very simple reason why less people die in the Netherlands: Because it's the Netherlands, full of Dutch people.
Look, I know what I am about to say is very politically incorrect, very cynical, but in the end, also very true. However, I will put it in a spoiler because I'm afraid that people these days might not accept the answer, because it goes quite against a lot of social movements of the past 50 or so years. What is the main cause of crime?
(And I strongly urge to you consider if you want to open the spoiler or not. I'm not breaking the rules here, but what it says is very extreme.)
Inequality.
And I know that you know that it's true, otherwise you wouldn't tell everyone you can to vote for a political party that tries very hard to ban not guns, but foreigners. When people of different cultures meet, you get trade and the expansion of ideas. You also get war, and the smaller cousin of war is crime.
The difference between the Netherlands and the US is that we are a country of immigrants, while the Dutch are all natives. It's only logical that the US will have more crime, guns or no guns. And considering that crime in the Netherlands is closely tied to immigration, you know what I just said is true.
If you read what was in the spoiler, I hope you have the courage to understand that I am not saying this to get a reaction or to troll you guys, but because it's simply a fact of life.
Edit: I guess I should mention it before any of you guys freak out: I don't like what I said here, and I do wish that it were different. But I cannot change the fact that in the end, what's inside the spoiler. I hate it just as much as you guys do, I just feel like this fact needs to be realized by society more.