Obesity and poor eating are often generational. Ignorance, poverty and misinformation can all be handed down at the same time as genetics. A lot of the parents don’t know they’re eating poorly. I don’t think the majority are knowingly harming their own children.

Friends of my family, couple of kids similar in age. Always severely overweight. Used to comment all the time about how scrawny me and my siblings were - we were healthy weights. Years later I caught up with one of them - they were practically unrecognisable. They’d lost a ton of weight and said to me that growing up they’d always been told the family was ‘big boned’ but by no means did they ever consider themselves overweight, let alone obese. They saw healthy weight people outside their family and thought they were malnourished.

Your world view is shaped by your upbringing. I’m sure there’s plenty of parents being neglectful or indifferent to their childrens’ health but I’d say plenty more have no idea what they’re doing. Add socio economic factors too, i.e. access to affordable fresh food, walkable cities etc.