I really don't - or shouldn't, need to post a thread about it. I'll bet if you do a search on this forum, you'll find a ton of similar posts about the problems of children and adults, riding without helmets.
If you really want to defend the 'no helmet' idea, tell that to a lady I met many years ago, when I went to see a horse she had for sale. I didn't end up buying the horse, but knew her on and off through the years. Her daughter, who was a reasonable little rider and competed here in S. Cal., was just coming back from a Saturday afternoon ride with some friends.They were all standing and talking, under trees on their property. My friend's daughter's horse, was startled by something and jumped to the side. The little girl fell off and hit her head. My friend has been taking care of this young lady now, for over thirty years. She remains in a semi-vegetative state. The little girl was twelve years old when it happened. She was not wearing a helmet. And I admit, in those days, I didn't always either. I did after meeting that lady and insist my own daughter did and my granddaughters too.
I didn't get off topic, but answered the OP. Just brought up a potentially dangerous situation, seen in the pictures posted.
Your opinion but as stated before it doesn't need to be commented on every picture of a kid/person without a helmet. Do you wear one on a bike, motorcycle? Well, guess what I don't nor do the kids on the bikes but they do on motorcycles. IT is a law in my state you have to wear a helmet on a motorcycle if you are under the age of 18.
You want to wear a helmet please do. If others choose not to respect their RIGHT not to :)