Read: What ISIS really wants

YouTube and Facebook, as private companies, are of course free to censor their sites however they wish, and I do not blame them at all for refusing to be a clubhouse for religious monsters. The U.K. has asked Zelin to password-protect his archive, which is already blocked or criminalized in other jurisdictions.

But I believe that Jihadology is different and should remain open to all. It enjoys moral safe-harbor, first of all, because unlike YouTube or Facebook it accepts no advertising and earns no click-based revenue. (Zelin offers translation services for a fee, but access to his archive is gratis.) No one profits from his collection. Second, he presents the specimens without endorsement or, indeed, explicit disapproval; unlike YouTube, it does not “recommend” videos, and unlike Facebook, it doesn’t favor certain pieces over others based on their popularity or clicks. The website is as close as one can have to a bare, unadorned catalog, coded only by source (Islamic State, al-Qaeda, Al-Shabaab, etc.) and date.

Even if Zelin took a salary, he would be earning it. These videos are valuable. Other than the traumatized pros who watch the videos for a living, few understand how much the propaganda can teach us about its makers and their intended audience. For the past four years, I have consumed many of these videos, sometimes peeking through my fingers to do so, and I can attest to their worth.

Read: War goes viral

Do you remember the grainy beheading videos from the early 2000s, when al-Qaeda began its series of snuff films, starring foreigners caught in its web in Iraq and Pakistan? Let me spare you from searching: They showed little of interest. The executioners’ faces were always well hidden, and the mise-en-scène usually obscured all details that might indicate the time of day or even the type of building in which they were filmed. The vibe in these videos is of an underground organization, safe only in its ratholes.

The Islamic State’s international success, and perhaps later failure, derived from its willingness to emerge into the daylight and show itself to the world. It was not clandestine. In practice, that means most of its videos take place in identifiable, and often identified, locations, and many feature subjects and spokesmen without masks, committing atrocities with pride and impunity in a world where they are heroes.

This world, available to us largely through the videos Zelin has curated, is a fantasyland stage-managed by ISIS. On that basis alone, some might dismiss the videos as worse than useless. But remember that the fantasy, not the reality, is what motivated tens of thousands of men, women, and children to migrate to Syria and Iraq. These videos, along with private messages from friends, lured people over in defiance of all sense, rationality, decency, and instinct for self-preservation. The notion that we know too much about this fantasy, rather than too little, strikes me as incurious at best. Those preparing to fight the next terrorist movement need to understand what inspired the last one.