I was taught a feel-good version of U.S. history in school and I remember the shock of learning about things like Japanese American Internment when I got to college; I was taught a Eurocentric version of World History that did not address cultures outside of Europe, especially Africa.
As a historian, my job is to look at the documents and interpret those documents based on corroboration of evidence across sources from multiple perspectives to arrive at an interpretation. Real history is messy and makes us uncomfortable at times. But it is through those experiences that we learn and grow in our understanding of the world as a complicated place. Students should learn the critical thinking skills that will allow them to be functioning members of society.
After teaching about race, class, and gender in U.S. history, I watched my students grow angry that they were in the last years of the public education and no one had ever mentioned these topics.
Research has shown that students who do not see their history in school do not do as well as their peers.