Being 'just a kid' is a good defense against a lot of things. For instance, if a 2-year-old cuts their own hair with safety scissors because their teacher has bangs and they were trying to emulate them. Or when a toddler rips the head off of their dolls- it's not a sign of sociopathy, they're just a kid. But the 'just a kid' excuse has an expiration date. Sure, I'd love to say 'But I'm just a kid!' after my dentist tells me I really need to floss more, but I am indeed an adult, and in charge of my own dental hygiene.
But it's up to the parents to find where that line is and enforce it, or else you'll be getting away with stuff forever. And we know what happens to a kid who gets away with stuff. They never stop. That's what happened in this story, and when their family members tried to set them straight, drama ensued.