Think about this, though: The heart of the nation’s military command is attacked, 184 are killed, and a memorial is designed based on victims’ birth years. It is as if the main point were the diversity of the murdered rather than the nature of the attack.

Some of the flaws in contemporary memorials may be related to their having become democratic signposts demanding attention for the dead in a crowded political marketplace where there is no clear notion of a public realm. But in the case of Sept. 11, this individualized approach may also be a form of avoidance, a reluctance to focus on the public significance of the attacks, their consequences, and the debates that continue.

The museum does, of course, recognize that these were attacks. And the exhibition’s second section is devoted to a survey of Al Qaeda. But it amounts to less than a tenth of the overall narrative; it is too narrowly conceived to convey the jihadist threat and its continuing evolution, let alone the responses and controversies it has inspired. Is it too soon for a more detailed history? It would seem so, but astonishingly, if the section about Al Qaeda were excised, little else at the museum would be affected; that is how disjointed the portrayal is. Without the Qaeda section, the narrative could almost be an account of a natural catastrophe.

We see this, too, in the exhibition’s closing gallery: a tribute to the idea of treating each Sept. 11 anniversary as a National Day of Service and Remembrance. We see images here of a church being rebuilt in Indiana, of rebuilding after the 2011 earthquake in Haiti, and of educational work in Afghanistan. In one respect, this turns the commemorations into homages to the sacrifices of relief workers and first responders. But it also involves avoidance. On the 10th anniversary of Sept. 11, when the White House offered guidelines for commemoration, it said that such efforts would show that we can withstand “whatever dangers may come — be they terrorist attacks or natural disasters.”

If attacks and disasters resemble each other, though, it is merely in individual experiences of trauma — this museum’s chosen domain — certainly not in the public consequences or historical implications of these events. Unfortunately, distinctions like these are now too eagerly ignored, perhaps because they bring up such unpleasant future possibilities.

But should they be ignored? Should this be the memorialization of Sept. 11 we are left with?