The same way you tell them that Daddy just burned Hamburg to the ground or that he just incinerated 120,000 Japs overnight.
Israel presents an example - an extreme example - of the mental disease that is consuming the US, Canada, and Europe. That is, the failure to teach children (and the failure of adults to understand) that the world is made up of "them" and "us", and that THEIR "right to exist" (or to be left in peace, etc, etc) is CONTINGENT on their behavior toward us.
Any Jewish child, anywhere in the world, who wonders "what did I do to provoke this anti-Semite?" does not know his scripture and has not been properly raised.
Big time bump....