In my opinion, "childhood is strongly institutionalized" means that the childhood of our children is strongly controled / influenced by institutions / authorities.

The definition of institutionalized is 'established in practice or custom' meaning that something becomes common because everyone else is doing it. Perhaps the sentence means that a kid's childhood experiences are limited because of what everyone else says is too dangerous, how everyone else is raising their own children, or how the parents themselves were raised as kids This question is kind of tricky. I hope this helped!