Why should they not learn about these things? You can't refute such things unless you at least know the talking points. Without knowing then you end up making a fool of yourself due to criticizing something you don't know about.
That depends on how far into the weeds you're looking to go.
A basic philosophy that all humans are worthy of respect is actually a much more effective argument against many of these ideologies than being able to quote the impact on production statistics via their use (or otherwise) of interned citizens.
Personally, I like being across both, but my 12 year old daughter approaches such issues in a simple and effective manner. How does the situation match up with her non-negotiable values?
People can make prima facie cases for basically anything. Give me a room full of 12 year Olds and enough time, and it won't end well (were I sufficiently motivated).
But the kid who wants to discuss the topic to death, and litigate every nuance is kinda easier to 'turn' in my experience. They've set up a premise where a logical discussion can be had.
Whereas the kid who has strong core values that they view all discussion through will be more challenging.
Just my take, not trying to convince you of anything. I'm kinda enjoying a chance to share opinions on something that's neither political or religious!!