More than 50,000 protesters at Sydney Climate Strike, page-121

"I am frothing at the mouth that these children were allowed to protest about something they strongly agree with!"

Children are being exploited. This is the ultimate poisoning of the politics of climate change when you use children to promote your untruths because they won't be questioned or scrutinised.
They are not informed or in control of the agenda. Responsible leaders should discourage anyone who wants to use children to front a political movement. The adults should be criticized here for using children in this way.
The law on this is very clear, on school days children are required to attend school and the behavior of the schoolteachers directly contravenes the policies of the department of education on political activities.