I think we're taking this waaay too seriously. Here's a list of 46 reasons a three year old might have a melt-down. 46 Reasons My Three Year Old Might be Freaking Out | Jason Good
Folks that haven't raised children may not get the melt-downs and tantrums. Sometimes it's about poor parenting, other times it's just the way children are.
Here's another list that makes you want to laugh, and feel some empathy for the parents 36 Reasons My Kid Is Crying... Temper Tantrums You Can't Help But Laugh At (GALLERY)
I get the odd temper tantrum in the candy or toy aisle. But in this case, the parents are the ones intentionally provoking the tantrum, are they not? Is it what parents do? I wouldn't know, I am one of those folks who did not raise children.