Yes, quite, I wouldn't be surprised. Or maybe it could have been due to political content, but maybe they have a good reason. Perhaps the whole reason they have these organisations is that delicate matters of international politics can be raised in a very neutral and controlled way. I have to point out that I'm not a diplomat or whatever and I've never organised one of these things (putting me in the same boat as pretty much every other Slashdotter commenting on this story), but imagine how pissed off you would be if you had spent all that effort getting important people together into a room from all over the world to talk about things with important global consequences, and the whole thing was scuppered because a bunch of idiots put up posters that led some of the delegates to believe that the hosting organisation was biased against them from the start or politically compromised in some other way.
Now I support free speech, I think it's a good and important thing. However, if everyone is packed into a room, all shouting their viewpoints at the same time so nobody can really hear or be heard above the din, then what bloody good is that? In that situation, I think that free speech would be best served by someone getting everyone to shut the hell up, then organising a way to let everyone say what they want to say without being shouted over by other people. I think the UN is like a much more complicated version of that situation there; you need to have strict protocols controlling how opinions are expressed and viewpoints are put across, or else the whole thing will descend into chaos.
Also, TFA has a quote:
"If we cannot discuss topics about Internet censorship and surveillance policy at a forum about Internet governance then what is the point of something like the IGF,"
Well, you can do a quick Google search and download a PDF of the conference programme. Apart from the hilarious mistake in naming one of the delegates as "Ms. Bruce Schneier", the programme also details a talk on Security, Openness and Privacy, which includes the following topics:
* The respect for privacy as a business advantage;
* Cultural and technical perspectives on the regulation of illegal Web
* Regulatory models for privacy;
* Ensuring the open architecture of the Internet;
* Enabling frameworks for freedom;
* Ethical dimensions of the Internet.
So perhaps they will be discussing those topics after all - but discussing them perhaps according to some stricter protocol for the reasons I mentioned above. Again, I'd like to point out that I don't actually know anything about all this UN conference business, I'm really just trying to point out that maybe there's something more complicated going on than some of the other comments on here are suggesting.