David Vigilante is Executive Vice President and General Counsel for CNN and Warner Media News and Sports. The opinions expressed in this commentary are his. Read more opinion on CNN.

(CNN) Many people of all political persuasions and backgrounds were rightly horrified at the videos that appeared to show high school students in an affluent Los Angeles suburb singing Nazi songs and making the Nazi salute. Sadly, this was just the latest incident of young Americans evoking this nightmarish past.

David Vigilante

But those of us who are appalled by these acts sometimes fail to see the full scope of the awfulness we are witnessing. Acts of racism and anti-Semitism are directed at particular groups, to be sure. Jews, immigrants and people of color have powerful reasons to fear white-supremacist, Nazi-sympathizing hatred and violence.

But the danger doesn't stop there. We must remind ourselves that this deplorable behavior harms all of us.

We fail one another when we Americans forget our history. And we do violence to the memory of those who sacrificed for us. The 1944 massacre at Malmedy during World War II is but one example.

By the end of that year, it was apparent to all but the most deluded Germans that the war was lost. Desperate to delay defeat, Adolf Hitler ordered what has become known as "the Battle of the Bulge," a last-ditch offensive that was meant not only to split Allied lines, but also to strike terror in the hearts of soldiers and civilians alike.

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