Done hand in glove with The Guardian, (a.k.a. the provisional wing of a school of thought that makes excuses for leftist authoritarianism,) behold a campaign directed at intimidating children to do their political bidding through operant conditioning - possibly because persuading intelligent adults is just too much to be bothered with. After all, it's a lot easier to inculcate a belief in a man-emitted carbon apocalypse in children who haven't yet developed a firm grip on science and the natural world.
Attempting to access children without the consent of their parents, employing tacitly inferred threats of violence and torture, these "campaigners" are using the tactics of cultists and pedophile sexual predators. I'm sure they've invented a morality for themselves that permits them to think that THEIR issue is more important than fostering the independent thinking of children, or the authority of parents.