I look upon this as I wold any tragic death involving a small child and something inherently dangerous. Swimming pools, chemicals, laundry "pods", running into a street, etc. When a small child is in your care, that child requires your extraordinary attention and care to ensure that the child doesn't get into something that can harm him/her. Guns included.
Touche'
That's the real issue right there isn't it? Yes, I do not agree with leaving a loaded and unsecured firearm in a vehicle. Kids aren't the only reason. Arming criminals who may break in my vehicle is a very real concern to me. Yes, I don't want one of my firearms stolen because it deprives me of my property, but more important to me is that my guns don't arm criminals. I do feel like stuffing a gun in the pocket behind a seat for days and forgetting about it is imprudent (a nice way of putting it). But at the end of the day, why is this a national story when it's not a national story when a toddler drowns in a swimming pool (a fairly common occurrence).
Actually since you posted that Skans I went to the CDC webpage and did some research. All data is from 2016 From ages 1-44 years old, unintentional injury is the leading cause of death (see chart in link below)
https://webappa.cdc.gov/cgi-bin/broker.exe
Motor Vehicle Accidents and Drownings are the top two causes of unintentional injury deaths from ages 1-14. They tend to trade places depending on specific age range. From ages 1-4, Drowing accounts for 33.7% of deaths, MV accidents for 26.5%, and accidental firearm deaths account for 2.7%. Story is quite similar for other ages. Here's a chart for ages 1-4 (if it works).
Also, for all ages unintentional injury is the 3rd leading cause of death behind heart disease and malignant neoplasms (whatever that is). Firearms were responsible in 0.3% of unintentional injury deaths across all ages. 0.3%, that's it. Suicide is the 10th leading cause of death, of which half were with firearms. Homicide was not in the top 10 causes of death, at least for all age groups combined.
As a matter of fact, pivoting a little, there were a little over 38k gun deaths in 2016. About 2/3rds were suicide. Drug overdose deaths, a form of poison death, accounted for over 64k deaths. I have been unable to find data on all other poison substances, they harped on drug overdose because of opioids.
All info from
https://www.poison.org/poison-statistics-national
and
https://www.cdc.gov/
At any rate, back to relevance of the OP. Yes this is tragic. Yes I believe the father (and possibly mother) was quite reckless. Criminally so? I don't know, if the he is a decent man he must be devastated and guilt-laden. Punishing him criminally probably won't do any more than what he's already going through, other than dragging it out. But the issue I do have is Yahoo profiling this because they have an agenda. There are many other, much more prolific, causes of death that don't make national headlines. Ok Yahoo, waiting to see a story about how you deem parents to be unfit because they had a toddler accidentally drowing in the home swimming pool. My bet is you won't see such an article there.