I don't think terms like "stupid" and "tragedy troll" help the conversation on Second Amendment rights. Bob Costas is sane, has an above-average IQ and doesn't appear to be the second coming of Mussolini.
Are there too many guns in the hands of young adults (especially football and basketball pros) at a higher risk of misusing them? Yes. That's the lion share of what Costas was lamenting.
The problem lies in what to do about that. Here's part of Costas' remix on the issue.
I never mentioned the Second Amendment. I never used the words gun control. People inferred that. Now do I believe we need more comprehensive and more sensible gun control legislation? Yes, I do. That doesn't mean repeal the Second Amendment. That doesn't mean a prohibition on somebody having a gun to protect their home and their family. It means sensible and more comprehensive gun control legislation.
As it turns out, they rightly inferred his left-of-center take on the issue. The problem with the Belcher case is that "sensible and more comprehensive gun control legislation" would have to tread deep into Second Amendment rights if you're going to stop Saturday's shooting. One guy. One garden-variety handgun. A reasonable amount of ammo.
Do we stop the ammo? That would make the right to bear arms meaningless if you don't have anything to fire. Could oversight of folks stocking up for a small civil war like the Batman theater shooter flag Belcher ahead of time? No. Limiting ammo purchases to a reasonable amount might stop Aurora, but not KC. It would also possibly flag recreational target shooters who practice an "unreasonable amount" from the persepctive of a gun control maven.
Do we stop the pistol? You toss self-defence out the window if you're restricted to long-guns.
Do we stop the guy from owning the gun in the first place? The answer there would be some sort of restrictive permit to carry a gun where you'd have to positively prove you weren't the type of angry person who is likely to misuse a gun.
Do you flag anyone going to a psychologist? Does the psychologist have a duty to pull the gun permits from anyone on the edgy side that might go off if things break the wrong way. If that's the case, you're going to severely discourage folks seeking help for emotional problems and tend to disproportionately pull licences from folks in stressful situations, like tough neighborhoods.
That starts running into 14th Amendment issues as well as 2nd, disarming poor minority communities, or at least the law-abiding members of said communities; the folks on the dark side will have their ways of getting their heaters.
Thus, there doesn't seem to be a reasonable way to have kept a gun out of Mr. Belcher's hands, unless your idea of reasonable includes disarming most folks under psych care.
Such "sensible gun control" would trod on a large block of modern sensibilities, like the rights of minorities, the rights of folks with mild emotional problems and that pesky right to arm bears (if they call them "sportsmen" shouldn't the prey get a sporting chance to shoot back?).