Some people, in both staunch anti-gun groups and even groups against it (NRA etc), bury their head in the sand and ignore the realities. Others weigh them - how many Afghan civilians have to die to wipe out al Qaeda? How many American soldiers will die or be injured in the process? How many American civilian lives and injuries does that save? Is it worth it? Those same types of questions should be the crux of any argument about gun control.
Most of us look at it that way - we believe that owning a gun is not an inalienable human right, so we must weigh the benefits against the deaths.
Those who view gun ownership as an inalienable human right don't like to be confronted with the humanity of the "risks," especially when it's the death of children, so there's a lot of cognitive dissonance so that they can remove the gun from the equation. They'll blame the father, the 11 year old boy, society, video games, etc, but refuse to put any of the responsibility on our gun laws. I pull my hair out at the cognitive dissonance and get to a feeling that they're incapable of seeing past themselves and their guns and some warped, dogmatic bumper sticker logic.
They want complete gun freedom more than they care about protecting innocent lives, even those of children, and they'll jump through hoops to separate the two.
Unfortunately, I'm not sure that there's any way to change their minds on this. They'll stick to the methods of separating the two in their mind and keeping gun laws out of the equation. Instead, the focus needs to be on those who are pro-gun rights but also reasonable enough to see that it's not a binary problem, of either all guns or no guns (
https://en.wikipedia.org/wiki/False_dilemma), and that anyone who supports any measure of additional gun control is going to be willing to accept some rather than none (ME)... So there's compromise to be had.
Unfortunately, the right does a great job on this issue of creating panic - "They're coming for your guns!". Let's be honest, do we not see this here? In reality, this is not the case. Most people who support gun control don't want to take everyone's guns, they want to take certain types of guns and take guns from certain people, while making sure those who have them are safe and responsible.
Hopefully, sometime soon, those who want more gun control can realize that there are some gun owners and gun advocates who aren't "gun nuts," but will be highly offended by being called that... whereas they might otherwise be open to discussion (I have hunters/collecters in my own family)... Meanwhile, hopefully those gun rights advocates will realize that there are some gun control advocates who don't want to take their guns away, but simply enact REASONABLE gun control laws.
If those two groups don't come together, we'll never get anything done.