Why are middle schools and high schools so obsessed with teaching about WW2 and the Holocaust?

I know it's important but it's like all we ever learned about from 6-12 grade. In history cl we would get through all the book up to WWII by about early March and no joke, the rest of the unit would be spent on WWII and we never got to Korea, Vietnam, the hippies, Reagan, Clinton and 9/11 at all. We read five different about the Holocaust in reading cles (Number the Stars, Boy in the Striped Pajamas, Diary of Anne Frank, Night and Schindler's List) but we only read one of Shakespeare's plays (MacBeth). I took a religious studies cl and when we got to Judaism all they talked about was the Holocaust like no other part of their history mattered. Is this just my school or it all schools? No wonder kids don't know any history we only focus on one part of it!