My own personal guess is that there's two reasons for this move:
1) The cost of containing damage from activist and/or religious hackers is higher than the income brought in by the offending site.
2) The loss of income from muslim clients is greater than the income brought in by the offending site.
Let's be clear - you have a freedom of speech in the US. And a freedom of religion. But you can't make Putnam Books publish to get your message out there.
We can do very little legally to protect our children from this kind of thing. That's just the way it is.
So Atrios and ThinkProgress and others are up in arms because CNN is reporting that there is intelligence tying weapons used against U.S. troops to Iran's supreme leader.
An authority is a person who can tell you more about something than you really care to know.