My immigrant grandparents never talked about their roots, or the Old Country, very much. Maybe my grandfather’s home village being burned down a few years after he came here as a teenager, or the pogroms my grandmother’s family fled, had something to do with it. To them, the point of America was to get away from centuries-old divisions, hatreds, and prejudices, to a land promising freedom for all regardless of heritage.

As I sat in the chill damp, under a massive open-air tent, with thousands of others, at the opening of the Holocaust Museum a few weeks ago, I thought of my grandparents, their families, and the hundreds of millions of others whose lives have been touched by the forces of hate.

I was cheered by the extraordinary diversity of those attending the museum opening. The crowd had plenty of Jewish faces and cadences, to be sure, but African-Americans, Latinos, Asian-Americans and gentiles of all origins turned out in high number. I sat between a black businessman with deep roots in Evanston, and a Jewish staffer for a North Shore temple who had brought an elderly friend.

Because of former President Clinton and the anticipated crowds, all roads to the museum had been blocked for at least a quarter-mile in every direction. This forced thousands to queue up for buses in drizzly parking lots as far away as Old Orchard.

There was something unsettling in this mechanized transport of persons to such an event, through police cordons. I did not see, but other attendees related to me, how on one route in, a small group of neo-Nazis stood by to protest or heckle. I was grateful that, upon arrival, we weren’t subjected to a search or metal detectors; ultimately freedom relies on trust as much as on security.

With the temperature raw and the misty rain unending, the long agenda, at least seventeen speakers and sprinkled with politicians, was intimidating. Fortunately, the program ran with incredible efficiency; considerately, few speakers took more than a couple minutes.

Master of ceremonies J.B. Pritzker, relaxed and eloquent, seamlessly tied together the history of the project with the introduction of the many luminaries, who included Nobel Laureate Elie Wiesel, Gov. Pat Quinn, and taped remarks by President Barack Obama and Secretary of State Hillary Clinton.

Mr. Pritzker acknowledged the many groups victimized by the Third Reich, and observed that Albert Smith, the mayor of Skokie who opposed a planned neo-Nazi demonstration in the 1970s that sparked the drive for the museum, was Catholic. He could have added that the lawyer who defended the extremists’ constitutional rights was Jewish, as were many ACLU leaders.

By 90 minutes into the ceremonies, some of the crowd who had arrived hours before the start time were drifting out, deeply chilled, even before Bill Clinton’s keynote. Most stayed.

The former president, hurt to be attacked for allegedly racial-tinged remarks during the 2008 primary, retains the empathic skills most of us remember. One poignant moment in his speech came when he paused after saying all of us struggle with “the forces of darkness,” which sometimes win out. Saying that too many have been dying for too long “because of who they are,” he also spoke with passion about Rwanda, and his experiences in working with survivors there struggling to reconcile a horrifying and evil chapter in their, and our, recent history.

The greatest lessons to be learned at the Holocaust Museum are those with the greatest universality. Our ideals mean we must vigilantly resist the ghettoization of anyone, in any way, for any reason. The roots of our greatest inhumanities lie in making generalizations about others who are different, whether that difference is a divider as historically large as faith or skin, or as small as occupation or neighborhood. A crude categorization does not necessarily lead to cruelty, but marginalization through labels is a necessary first step down that path.

Looking past the superficial to the core of what makes a person is a necessary first step on a path to greater humanity.