I don’t think this would ever happen to me either BUT people are human and sometimes they do make mistakes like this, as proven by just how many stories there are like this.
I know of someone whose child died because they took their eye off the ball when they were tired. They got distracted, a moment in time that did not sum up in any way, the amazing and attentive parent that they were. They were, and still are, grief stricken years later and they will never be properly ok ever again. I’ve heard many similar stories of very good, loving, attentive parents making a mistake and suffering the worst possible consequences.
Many of us will have had ‘near misses’ with our kids, some of which we probably aren’t aware of because we are the lucky ones who didn’t face any, or any big, consequences for them.
It’s best not to judge what could be a terrible tragedy and what the parent will have to live their whole life with. I believe on a bad day, when we’re distracted, tired or something, it could happen to many of us. Presuming this was an accident, I have nothing but sympathy for the person who left their child in the car. I don’t know how parents get through things like this.