It's not about protection from dangerous ideas, it's about arming the populace with the tools to more readily determine for themselves which ideas are dangerous, and to protect themselves.
And the thing is, you don't really need to fool all the people, just most. Unfortunately, it seems that willful ignorance is the norm in many areas, and while I agree that reality has a tendency to win out in the long term, it can do a lot of damage in the short term.
What you're saying sounds good and is one of the reasons for the creation of public schools. But it also creates an opening for government indoctrination.
Then there's the opposite problem, privatized indoctrination where billionaires like News Corp's Murdoch get to influence millions with his propaganda.
Then the internet was supposed to save us but it turns out people like living in their own indoctrination bubbles and the internet is more than happy to provide it for them.
Starting out by teaching them to recognize indoctrination would be a good step, then. That's a fairly core part of critical thinking anyway, recognizing bias in the speaker.
And the thing is, you don't really need to fool all the people, just most. Unfortunately, it seems that willful ignorance is the norm in many areas, and while I agree that reality has a tendency to win out in the long term, it can do a lot of damage in the short term.