How is this not considered wrong?

I recently heard that a British primary school teacher told her class of 4 year olds that climate change is indisputably happening. This lead them to become eco zealots, but surely, in the democratic, free thinking and speaking West, kids should be allowed to make up their own minds? In my school, our Geography teacher brainwashed into believing it, but our science teacher a year later gave us the unbiased facts and we all realised how insignificant the changes were (of course its a new high, this is the industrial age, but there will always be a new high), so how did she get away with this deceit?