Gun worship and gun worshippers.

No, Captain Reinfeld. This is not a tragedy you've seen play out internationally.
This is pretty much a US specialty.

I remember a case in Arkansas in which two elementary school boys took a rifle from the grandfather's home and killed fellow students from a distance. All kids must be made to understand that such a threat is not an appropriate joke.

At 12, he fucked his life up...

So this kid probably hears about all the school shootings that take place in this country and the message he comes away with is 'I should tell people I'm gonna do that too.'

Stupid little shit.

I'm so grateful every time people like these are stopped in time!

With the continual problem of school shootings in the USA all threats must be taken seriously. I remember when the UK had a shooting at Dunblane. It was a shock. I hear about another shooting at a school in the USA and I think 'how many this month'? Then of course POTUS45 send thoughts and prayers - yawn.
Well it's on my study list about American society, politics and criminology for the academic year.

It gets worse, we must do something

Things like this should never be or never have been taken lightly, as a joke. Since 911 and then the media's attention to more shootings, these happenings have finally been regulated to "check it out." Even if the kid was kidding, he needs help.
Remember the hijackings of the 70's - I was on a plane in 80 that was delayed because some idiot made a hijacking joke. There are certain times and places where what you say is NOT protected speech. You can't yell fire in a movie theater; however, you can shout god isn't real.

Bloody 'ell!