My friend grew up in Greektown in Toronto (Canada) and had education classes two nights per week in their cultural heritage (run by the local ethnic community). It was not until 20 years later that he realized how indoctrinated he had been by these lessons, how he had been taught to hate the Turkish people for actions that had happened two to three thousand years ago.
I am not picking on the Greeks here, this is just a personal example of what goes on everywhere in the world to this very day.