One of Glenn Greenwald’s commenters gets to the bottom of it:
Don’t be fooled into thinking that this applies only to African-Americans. The sense of threatened tribalism is at the root of movement conservatism, and always has been.
[...]
Take almost any one of their “thoughtful” screeds about Islam and do a global search/replace from “Islam” to “niggers” and the text becomes instantly recognizable. This racist energy had for a long time been at least partly directed towards “the Communists” but now that it isn’t it is pretty much clear that Islam is now the designated nigger.
[From One of Instapundit's favorite blogs speaks on race - Glenn Greenwald - Salon.com]
Movement conservatism has always needed an Other to focus it’s adherents’ minds on. Communists, liberals, muslims, it’s always changing. “Standing athwart history and shouting stop” is about right: never thinking, never examining, only standing in the flow and hoping to turn it back.