US gun nuts you speak of use our firearms to stop a crime or for self-defense between 1 to 4 million times a year depending on who's estimate you use. But let's take the one million figure:
Without our firearms, we would have over a million more violent crimes each year. We have plenty as it is now. We don't need to be inviting more.
In almost all cases of mass shootings, the perpetrator makes sure they use a target where the people are disarmed. They don't want any resistance. They want to kill as many people as possible, and using a target of people where some may be armed is a situation they avoid.
As the NRA has said repeatedly, the only way to stop a bad guy with a gun is a good guy with a gun, and that's been proven correct repeatedly. Those kids were all sitting ducks until the border patrol special forces arrived to take down the gunman. He made sure to choose a school where defense was as weak as possible, and never considered those special forces being nearby.
Here in my city we hosted the Republican National Convention. Because it was Donald Trump, the leftist terrorists promised us it would be a blood bath; people coming from all over the country to cause trouble; people being pulled out of their car and seriously hurt or killed. The result? Three arrests, and one of them was not even related to the convention.
Why was that? Because these threats came from people in commie states with strict gun controls and little legal protection for a victim that uses a firearm for self-defense. Oh, in their cities they started police cars on fire, pulled people out of their car to beat them, even tried to burn down federal buildings. But in our city and state, you try to break into somebody's car to cause harm, it may be the last thing you did in life, and our laws strictly protect the victims that take down these lowlifes. So we had a pretty peaceful event.