It must have come as a disappointment to the mullahs of Mazar-e-Sharif—who sent the faithful out on Friday with instructions to avenge the recent insult to the Quran—and to the mobs who consequently went forth to slaughter 12 people at U.N. headquarters, nine more in Kandahar the next day, and two more the next, that their bloody enterprise had counted for so little in the eyes of Western military leaders.

So it would appear at least from the response by Gen. David Petraeus, who delivered an impassioned rebuke of a publicity-hungry Florida pastor who had presided over the mock trial and burning of a Quran on March 20. This act was, the general declared in a video statement over the weekend, “hateful, extremely disrespectful, and enormously intolerant.” It had endangered American troops. He wanted, he announced, to condemn it in the strongest possible terms.

ASSOCIATED PRESSAfghans chant anti-U.S. slogans in Mazar-e-Sharif, April 1.

No one listening could doubt it. The general would go on to say more, but nowhere in any of that condemnation was it possible to find a mention of the merciless savagery that had taken place in the name of devotion to God and the Quran. Mark Sedwill, the NATO senior civilian representative who joined Gen. Petraeus in the statement, did manage to find a moment to murmur in passing that, of course, condolences were due to “everyone who has been hurt in the demonstrations.”

It’s hard to conceive of a pronouncement richer in evasions of brutal reality than this one, with its references to people “hurt” in “demonstrations.” The participants in these “demonstrations”—a nice touch, that, suggestive of marchers, perhaps carrying placards—had in fact hunted down and killed, by shooting, stabbing and beating to death a total of 22 people by the end of the third day’s expression of religious devotion.

In an interview Sunday in this newspaper, Gen. Petraeus reflected further on the problems caused by burning the Quran and how mobs could be influenced by those who might have an interest in hijacking passions—”in this case, perhaps, understandable passions.”

To this the only sane response is no. They are not understandable, these passions that so invariably find voice in mass murder, the butchery of imagined enemies like the people hunted down in the U.N. office Friday, and of everyone else the mobs encountered who might fit the bill. We will not prevail over terrorism and the related bloodlust of this fundamentalist fanaticism as long as our leading representatives, the military included, are inclined to pronounce its motivations as “understandable.”

It should be said that President Obama, to his credit, went on to declare, after denouncing the Quran burning, that to kill innocent people in response is “outrageous and an offense to human decency and dignity.” It should be said, too, that it’s a bleak commentary on the prevailing political atmosphere that the president’s public recognition of the horrors committed by those rampaging soldiers of Islam should seem noteworthy.

Still, it was. And it came as a relief, after so much handwringing, all of it focused on the Florida pastor and the likelihood that he may have endangered American troops. (The same was said about the danger to American troops when Newsweek published a false report, in 2005, that American interrogators had flushed a Quran down the toilet—an event which set off days of rioting and bloodshed in Afghanistan and elsewhere.)

By making no mention of the perpetrators of the current massacres—while managing to suggest they were understandably driven to their action—Gen. Petraeus doubtless believed he was taking the appropriate politic path. It’s a path that’s unquestionably familiar—called appeasement—and one whose usual outcome is also familiar.

Displays of cringing deference to the forces loosed on the streets of Afghanistan over the weekend will not strengthen the American mission. They will stiffen the spines of the jihadists. Such displays count as victories, reassuring indicators that the threat of terrorism—mob terrorism, in this case—continues to work its wonders as a weapon of war. The sort that could send the commanding general of U.S forces in Afghanistan and a NATO official into swoons of apology while denouncing the pastor’s act. For a moment there during their joint statement it seemed altogether possible that one or another of them might begin rending his garments.

That none of these emotional proclamations included any judgment, moral or otherwise, about the criminality of the zealots who had just taken so many lives, speaks volumes to those at war with us—all of it encouraging to them. Something to consider adding to the list of things that might endanger the lives of American troops.

Ms. Rabinowitz is a member of the Journal’s editorial board.