Now that Glenn Greenwald has rescinded his invocation of Riefenstahl as being "too inflammatory and extreme", and before we get into a debate about whether the rescinding was sufficiently apologetic, let's take a side track for a moment.
Just about everyone on both sides of the issue of the innocuousness/egregiousness of Greenwald's original tweet agrees on a premise: Glenn Greenwald compared blackwaterdog to Riesenstahl. But did he?
Greenwald actually wrote
If Leni Riefenstahl were an Obama fanatic and had a blog, this is exactly what it would look like.
But he could have written this instead:
If Leni Reifenstahl were alive today, she'd create a blog exactly like BWD's.
He's right to temper the rhetoric, because the problem with provoking an emotional response to his tweet is that we're not likely to notice the difference between his real version and my false one. If you do see the difference, you can begin to question whether Greenwald was really comparing BWD to Riefenstahl and therefore whether there was any comparison between Obama and Hitler, intended or not.
Condensing the blockquotes may make their difference clearer. The actual tweet essentially says
If Reifenstahl had BWD's attributes, her work would look the same.
The false version essentially says
BWD is just like a 21st Century Leni Reifenstahl.
Most of the response to Greenwald's tweet glosses over the condition that begins and limits his analogy: "If Leni Riefenstahl were an Obama fanatic." Note that Greenwald doesn't assume that Riefenstahl would be an Obama fanatic. It's likely that Greenwald doesn't assume that not because Riefenstahl didn't tend towards fanaticism nor because a German supporter of the Third Reich might not be a fanatic of a black American president (I don't think Greenwald cares about historicity in his tweet), but because he doesn't assume that Obama would appeal to her.
Riefenstahl has two relevant attributes for this discussion: 1) a master of propaganda and 2) an idolater of charismatic fascism. People who are angry with Greenwald's tweet believe that Riefenstahl's second attribute is being projected onto BWD, and even more than that, that charismatic fascism is being projected onto Obama. If that were the case, though, there would be no reason to include the condition in such a succinct tweet. Greenwald would assume implicitly that Riefenstahl would be a fanatic of Obama.
Secondly, Greenwald's actual tweet concludes: "...this is exactly what it would look like." The comparison is the visual imagery of the blog and nothing else. In other words, any other comparison between Riefenstahl and BWD is inferred or projected.
This may be too close of a reading for some, but that's exactly what a distaste for shoot-from-the-hip reactions requires.
For an excellent discussion of propaganda, check out Seneca Doane's recommended diary