Schools should allow children to wear face masks when indoors at school, otherwise other prevention measures may be in vain. Children playing and studying together may come home and infect their families. Who will take care of children whose parents/carers have been needlessly infected?
You may be interested in these active petitions
There are still some people who are not very concerned about the the Covid-19 pandemic, either due to bravado, misconceptions or inertia.
People with a more cautious attitude should be given the chance to maintain their own hygiene standards, and not have to send their children to schools where they may be even less protected than in shops, which are likely to have better ventilation systems and yet masks are required!