Because their immune systems are shot from the lockdowns, no exercise, bad diets, mental health fucked due to isolation which further increases stress levels and depression which in turn tanks the immune system etc etc..
There is no evidence to support your claims. There is evidence that many people are suffering from long covid. That covid can damage the pancreas, leading to diabetes, that it damages the kidneys, and of course the lungs.
Two years into this pandemic, and people are still debating whether it's real??? How many right wing politicians, radio hosts, and podcasters have to die before you take it seriously?
If you're so concerned about the children, what are you doing about "active shooter drills" ? These affect the mental health of children much more than zoom classrooms.