The big issue here is: young children aren’t affected statistically in significant numbers... So they’re minimizing the effects on a pop that’s largely “less affected”.
On the other hand parents are very likely to get it from their kids if the kids do get infected.
Anyway, how do they expect kids to practice good sanitation when attentive adults can fail (sure kids have less to worry about and can be very focused —if trained properly at home and school).
I think a measure like this is more symbolic than effective... but hey...
How will kids beginning school even learn how to develop normal kid interaction and friendships ?