It is true that the idea of protecting our children in this day and age almost seems to be a luxury, when one considers the lack of childhood many kids in this world get to have. But I still feel it important to protect kids as much as possible from the ugliness of life until they are ready emotionally to handle it.
Yes, of course, I will want my children to learn about the Holocaust - to forget history is potentially to repeat it - but it needs to be when they are of an age to fully understand what it means without being emotionally fried from the experience.
I took a semester-long literature course in college about the Holocaust - we read many different things about it, and it was so incredibly horrifying, I felt emotionally sunk by the end of the semester. A great class, to be sure, but if it affected a college junior that way, think what it could do to middle-school kids?