In doing diversity training, I've learned that people need to be exposed to differences earlier on in life. If they wait till later on, they have formed a certain inveterate mindset on their own beliefs already and that's very hard to correct.
So, if a person grew up knowing the only way in life is to destroy all others that aren't like them, then by age 13 or 15 or so, they'll feel that's the way the world has to be.
I'm a good example. I grew up fishing for survival in the farms and on the refugee run. I think all people need to know how to fish at least. If they don't know how to fish, they have no character. That's my belief. I continue to believe so. Man, despite whatever else you do in life, at least know how to handle a fishing pole.