Oops!
I second the applause for Mrzzy and agree how we educate people to appreciate when something is factual and when it is a feeling that contradicts facts is certainly important. (Though I am not convinced there was ever a time the population was good at it and call in evidence demagogues and rabble routers though recorded history). I also agree the kind of books Senoufou mentions are useful in that regard, but they are mainly about different views of the same thing (a historical event for example). Used badly, of course, they can make things worse because they could leave the child with the belief all viewpoints are equally valid, which is the exact opposite of what we are attempting to achieve. So surprise, surprise, a good teacher is an essential part of the mix.

Another thing I think is well intentioned but counter productive is the separation of subjects. We end up if we are not careful with a strong emphasis on the importance of factual accuracy in science subjects with (comparatively) little emphasis on facts in other subjects, as in the "alternative views" of history approach when taught badly.

I always remember visiting countries in Scandinavia and hearing how a particular king was seen as a glorious unifier in the country he originally ruled and a vile oppressor in the country he conquered. You need quite a sophisticated understanding of 'fact' and 'viewpoint' to cope with that, and I don't think you get that with a "copper gives a greeny blue flame test' idea of facts. The result is that how people think of facts when they are dealing with one subject is separated from facts with another.