This article isn't outrageous, it's plain stupid. Nursery rhymes put kids 'at risk', where it talks about 'first responders' to Humpty Dumpty. Indeed.
These "Canadian Researchers" need to go and find something better to do. These nursery rhymes were written several hundred years ago and reflected contemporary themes. Humpty Dumpty referred to a king who had fallen from power. I don't remember who or when. The part about the kings men and horses meant they couldn't return him to power. "Ring around the rosie"? That referred to bubonic plague. And so on.
To try and bring a modern context to these tales is ridiculous. They are historical similes to talk about terrible events and nothing more. They are songs or short stories that have lost their meaning in the sands of time and it should stay that way. If a child is very inquisitive on the subject, look it up together on the internet. I'm sure the answers are easily Googled.