Denn, so schließt er messerscharf, daß nicht sein kann was nicht sein darf.

(Because - he concludes in clarity - nothing can be what is not allowed to be, a part of a famous German poem)

It's a political ploy: If children don't go to school, parent's cannot go to work. This hurts the economy. A certain number of Covid deaths is acceptable as long as the economy is not hurting.