Who is more infantile in that shooting incident with the 5 year old? The child - or the adults?
Anyhow, if adults are clever enough to give a 4 year old (he got the rifle one year before, I read in German articles) a functional rifle as a present, then they should also agree to now throw the full weight of the law onto the boy and lock him away for the coming decades. I mean if a 12 year old some years ago got lifelong for having stolen something to eat for the third time, then this 5 year old monster really should be made regretting what he did as well, don't you think?
Selling toy packages "My first rifle" for children rifles dedicated to kids. That is pathological, and mentally disturbed.

Let them come of age, and then , when they are ripe by mind and character, train them with the real things, where one considers that to be necessary.
This story again illustrates this insane fetish that weapons serve as in American culture. Where the
sober mindset that sees them as a
tool designed for very specialized purposes exclusively is missing, selling weapons should be forbidden. Churches give bibles away for free or at very low subsidized prices over here. I would not be surprised if somebody some day tells me that the NRA also runs projects like that, and gives away firearms for kids for free, or at subsidized, very low prices.
"Takes more than combat gear to make a man,
takes more than a rifle or a gun..."