I think what air was saying is that in the US, propaganda, of any sort, cannot be a crime, due to the 1st amendment to the US constitution. That is freedom of speech.
Well, it could be so de jure in USA. But de facto we see opposite. Snowden mentioned unconstitutional violation of human rights of US citizen. And now he is hunted by US government, seriously hunted.
He did more than just 'mention' it, he stoled government property and disseminated classified information to the public. I'm not saying what he did was 'wrong', but it is illegal and not particularly a free speech issue.
I'm not sure how anyone could say Russia's 'way more open' with a straight face[1].
These people didn't negotiate this meeting. This is the formal reason.
Informal reason is that they are often organized by the institutions which funded by other countries, institutions, which aim is definitely not a prohibition of Russia.
May be it is a good idea to avoid judgements about countries/cultures, which you don't understand?
Russia is way more open in this perspective.