The bizzare thing is that the claim started with a study that wasn't entirely dishonest, just bizzarly conducted. The study was then twisted into the blatant lie that we hear all the time.
The original study out of the University of Michigan was honest enough to use the words "children and adolescents" (emphasis mine). This is at least slightly more honest than just saying "children." Still, they were cooking the books. Half of the reported deaths were legal adults. They included everyone under the age of twenty except for people under the age of one. So, they got away with omitting all of the deaths by non-firearms that happen to the youngest, and most fragile humans; while, at the same time, they included young, legal adults, who are at the age that's at the peak likelihood to engage in criminal behavior.
Still, I know this because they said it in the study. It's stupid reasoning; but, at least they told us.
When NPR and MSNBC and the like got wind of this study, they just dropped the word "adolescent" in their reporting, and started linking this lie to the lie that we've had more than one mass shooting a day in this country, and just counted on the lie sticking. Unfortunately, the lie has stuck, and I'm one of the unfortunate people trying to fight the uphill battle to get some people to see the truth.
Still, there's an important question. Why do so many freaking people believe this lie?
I'm not gonna be cheap and simply say that people are lazy or stupid. That's the case with too many people; but, it's not that simple.
Really, I think that going with that explanation is too charitable to the other side.
I don't believe that everybody repeating this falsehood is a moron or an ignoramus. If you're not stupid, and you're not ignorant, and you're repeating something that's false, it can only be concluded that you're a liar.
Still, why did leftists hop onto the falsehood with such alacrity? You don't repeat anything twenty times a day unless you enjoy hearing it coming out of your mouth.
Well, just like everything else with these people, they want it to be true, because it makes children useful to them. They don't see moral philosophy or politics as a real and honest challenge that we're all struggling with. They view it as a game to be won at any cost, and children are the weak but useful pawns in the game.
I don't think that it really matters to them whether they get people on the correct side of this issue to believe the lie. It's simply a matter of polarizing their group mixed with a particular desire to engage in some mental masturbation. It's the same reasoning behind the lie that, if we don't chemically sterilize kids, they'll all kill themselves, despite the fact that the data show the exact opposite.
They wanna get and use 'em while their young, just like every authoritarian regime has done throughout human history.