I'd wager that the difference is that your chances in the US, Australia, or the UK that a bunch of thugs kicks in your door at three am, grabs you and disappears you forever are a whole lot smaller than in some of the real oppressive countries.

I'm not claiming that everything is perfect in those western countries, but compared to them there are some truly evil regimes around in countries where absolutely no checks and balances exists to rein abuse in.

While this may get me down-voted into oblivion, since the author may be easily one of the most hated people in the tech world, I recommend Evgeny Morozovs "The Net Delusion" which is a quite insightful take on the abuse of tech by oppressive regimes.

It depends. Countries like the US are ruthless to those whom they consider enemies of the state or traitors, but let's be honest, the qualifications to be an enemy of the state are much higher in the US than they are in a country like Tunisia, Pakistan, or Iran. The FBI is not going to plant malware on your computer just because you say "fuck Obama" or are planning a protest, but this could very well happen in many oppressive countries.

The US treats certain people very unethically, including Assange, but in these cases it's more a sense of vengeance for having our top secret dirty laundry aired, compared to simply disagreeing with or disliking the government. We still have a long way to go to, but the freedom to express yourself is simply a lot higher in most Western European and North American countries.