When I was growing up as a Nice Jewish Boy in day school, we were taught that the Crusades were one of the worst episodes in history: marauding Christian soldiers massacring everyone in sight. Especially Jews.

Most historians tend to agree that the Crusades were a dark chapter in Christian history, with extraordinary violence carried out in Christ’s name, and with Christian doctrine often a mere excuse for murder and pillage. This, no doubt, is why President Obama mentioned the Crusades as an example of heinous religious violence last week.

It would seem to be an uncontroversial claim. Historians estimate that between one and three million people died in the Crusades (including the Crusaders), at a time when the world’s population was 300 million. That’s right—up to 1 percent of the entire world population perished in the paroxysms of violence between 1095 and 1291. The equivalent of sixty million people today.

The right-wingnut controversy following Obama’s remarks, however, has laid bare a troubling trend among conservative Christians (and the politicians eager to pander to them): They are now in the business of justifying the Crusades.

You read that right. The point being made is not that Obama is wrong to compare ISIS to the Crusades because the Crusades happened long ago (this was Bobby Jindal’s cute, misleading quip), or because the historical context is different. It’s that Obama is wrong to compare ISIS to the Crusades because the Crusades were actually a good thing.

Perhaps the leading theme in this literature is that “The Crusades—despite their terrible organized cruelties—were a defensive war.” This was thusly emphasized Jonah Goldberg in the National Review. (Goldberg proceeded to quote Bernard Lewis, “the greatest living English-language historian of Islam,” apparently unaware that he is the primary target of Edward Said’s book Orientalism and has been shown, time and again, to have anti-Muslim bias.)

Ross Douthat, writing in the New York Times (which presumably continues to give him a platform in order to show that religious dogma can cloud even an intelligent mind), described the Crusades as an “incredibly complicated multicentury story.”

And these are the smart conservatives. Here’s Rick Santorum:

The idea that the Crusades and the fight of Christendom against Islam is somehow an aggression on our part is absolutely anti-historical. And that is what the perception is by the American left who hates Christendom. They hate Christendom. They hate Western civilization at the core. That’s the problem.

“Somehow an aggression on our part.” The Crusades were really just defense.

Behind this sort of posturing is a bookshelf of revisionist history, most of it written by apologetic Christians—“apologetic” in the sense of an apologia, a defense, not an apology for past misdeeds. For example, apologist Marco Meschini, a professor at a Catholic university in Milan, has written that crusades are defensive while jihad is offensive.

One of the leading debunkers of the biased misuse of history is Professor Matthew Gabriele of Virginia Tech, who has taught and published widely on the Crusades. On his blog, he said simply, “I call bullshit.”

In fact, as Gabriele writes, various Muslim sects had controlled Jerusalem since 732 , yet it took the Christian forces 350 years to “respond.” And only the first of eight crusades was dedicated to retaking Christian shrines; subsequent adventures in Egypt, Tunisia, and modern-day Syria and Turkey were not so motivated.

In any case, is it sensible to take the Church leadership’s rhetoric at face value? Sure, the Crusades may have been justified by religious objectives. But scholars have observed for centuries that they were at least equally motivated by the Church’s centralization of temporal power, the authority of monarchs friendly to the Church, and the accretion of wealth.

Another leading theme is that violence is central to Islam, but peripheral to Christianity. Here’s Meschini again: “Jihad is the sixth pillar of Islam… On the contrary, there is no sacred Christian text that speaks of war in a similar way.” In response, Gabriele cited “the biblical books of Joshua, Judges, Kings, Maccabees” as well as “Augustine, Eusebius, the Pseudo-Methodius, the Tiburtine Sibyl, Adso of Montier-en-Der.”

Oh, and note that there are only five pillars of Islam, none of which is jihad. Meschini just made the “sixth pillar” stuff up.

Similarly, Notre Dame scholar Steve Weidenkopf, in a “a crash course in the Crusades” in the Catholic magazine Crisis, wrote it is a “myth” that Crusaders slaughtered all the inhabitants of Jerusalem, but in the same post, then says that it was “standard practice” to do so and “both Christians and Muslims followed this policy.”

So, they didn’t do it, but if they did, everyone did it anyway. Following the classic “No True Scotsman” fallacy, Weidenkopf then says that the Crusaders who massacred Jews—5,000 in the Rhineland massacres alone—were “brigands” and “cannot accurately be called Crusaders.”

In fact, the Crusaders massacred, massacred, and massacred some more. They massacred Jews in the Rhineland, Albigensian heretics in Spain, Muslims in the Holy Land. Sometimes (as in the Rhineland) the massacres were condemned by religious authorities; other times (as in Spain) it was actively encouraged.

And then there’s the selective appropriation of Crusade historiography. Interestingly, the multiply-knighted Cambridge historian Jonathan Riley-Smith has written several revisionist books on the Crusades which are selectively quoted by conservatives. Reacting against the materialist account of the Crusades—that they were economic enterprises, motivated by early colonialism—Riley-Smith has maintained that they were religious in nature. But he also pointed out that the Crusades were not just against Muslims, and not simply reactive. And Riley-Smith’s point that the Crusades were religious enterprises actually cuts against contemporary voices who try to distance them from Christianity.

These points are omitted in popular conservative appropriations of Riley-Smith, which basically take the good and leave the bad.

To be sure, radical Islamists have their own distortions of the Crusades. ISIS calls all American and European soldiers “Crusaders.” Sayyid Qutb’s iteration of “Crusaderism” (sulubiyya) is foundational to radical Islamism. Contrary to conservative rhetoric, however, no one in the West is really arguing that Muslims are justified in taking revenge on the Crusaders, or that radical Islamism is a reasonable reaction to the events of a millennium ago. That’s not the point.

The point is that whitewashing of one of the most bloody periods in world history is troubling on many levels. First, it is a radical failure to ‘own’ one’s own troubling history—like the same conservatives’ claims that slavery wasn’t really so bad and that the Inquisition, too, was sort of a good idea. It brings to mind Santayana’s overused quote that those who cannot remember the past are doomed to repeat it. But it’s even worse than that: This sort of revisionism tries to cover up the past and pretend it never happened.

Second, what’s the lesson here? That if Muslims attack Christians, a massive war effort that kills 1% of the world population and massacres innocents is an appropriate response? That Christians are just better people than Muslims, a la the “Clash of Civilizations?” That Christian power is the only kind of power that can’t ever be abused? None of these conclusions is defensible, or even morally tolerable.

Douthat, in his Times column, said that it’s “Niebuhrian” (as in the liberal theologian Reinhold Niebuhr) to recognize that we all have our flaws, that no civilization (and no individual) is perfect. Strange, I thought that was just Christian. But I know for sure that it’s wise.