Editing, yes, but on an epic scale—and critics are absolutely right to raise some stark questions. What precedent does this set? What actual policies are at work? Are the policies being applied consistently? If it's appropriate to take down these videos and pictures, why not the images of so many others who've been the victims of ISIS and other criminals?

All are important questions, but the reason they're so important, again, is the clout these services exert in the information marketplace. There was little uproar, after all, when the anything-goes LiveLeak—which hosts videos that most others find beyond the pale—vowed not to post any ISIS beheading videos, on the reasonable grounds that it’s wrong to help murderers do public relations.

What makes so many free-speech protectors fret in the current situation, again, is not the instinct to protect an unwary public from encountering the worst of humanity, or to avoid helping barbarian propagandists. It is the slippery slope issue, and this is getting more worrisome every day with the growing domination of Facebook, Google, and Twitter over our media flow.

They’re dominant not because they’ve taken control, but because we’ve given them control—and not for all bad reasons. These services are enormously useful and convenient. But because we aren’t paying for these services, we users are, as the saying goes, the products being sold to advertisers. We have no rights beyond what the companies give us in their terms of service, where quaint ideas like the First Amendment have no application. When Facebook decides what you see in your timeline, you have no recourse—because you “agreed” to terms of service that are grossly one-sided and not constrained by the Bill of Rights.

I’m a frequent Twitter user, in part because the company has for the most part been a strong protector of free speech. I confess to some misgivings about my own tendency to put so much of what I do into a proprietary service that increasingly makes clear that it controls the experience. Even as it was taking down the Foley videos, Twitter was expanding its unilateral tweaking of users’ timelines,inserting posts that the users did not ask for—a major breach in the bargain Twitter made with us from its early days. (I don’t trust Facebook at all, and use it rarely, and have been using DuckDuckGo, which doesn’t track users, as an alternative search engine—though I do use some Google services.)

Journalists have been especially short-sighted in their eagerness to use social networks, feeding enormous amounts of content into third-party services they do not in any way control and which get, by far, the best of the bargain in the long run. Guess what, journalism companies? Facebook is going to be your biggest competitor in the long run. Twitter is a media company, too. And Google’s eating your lunch every day.