What a bizarre reaction.
Firstly teachers have not arranged this event.
Secondly teachers do not run the schools, the Government (or local authority does).
Thirdly the Government are not lefty, nor are most local authorities.
Fourthly teaches come from all sides of the political spectrum, not mainly lefty or righty.
Fifthly, this is a worldwide event, not solely British.
You may consider climate change to be a waste of time. But to liken it to Naziism is just plain stupid. It is not propaganda, it is a theory, that needs to be discussed, and people make their own opinion and decisions about.
A large number of adults believe it and tell their children, who then protest about it.
Not sure I agree with children striking from School, or indeed being actively political at a young age. But it is not the dawn of a new third reich.