Technology has become an enabler
It's often a feature of "young" nations to have their politics coloured with a certain degree of xenophobia and conservatism (usually this is called "patriotism").
What has happened now though is that it is possible for someone in power to prevent access to anything they find distasteful or immoral or politically embarrassing with very little effort, this could not have been done with physical media without a very large number of people patrolling the border and checking everything that goes in and out of the country.
Essentially the same process is going on all over the place to different degrees: New Zealand appear to be following Oz (but with less media coverage), China is already well entrenched (but that is already starting to change as they become more reliant on trade with other countries and the hard line leaders begin to die off).
I expect Russia to start rattling its sword a bit more in the future now it's getting used to life without the extremes of communism it used to live under.
The UK is still getting used to life without an empire (or rather, the people in power are).
The US is starting to show signs of growing up, but still has some way to go.
Anyway, you probably get the picture.