"This is a fight over the future of Europe, and the people who are currently strangling the Greek economy in a transparent attempt to intimidate the Greek electorate understand this very well. That is why they are being especially aggressive and ruthless at this moment:"
... It is not surprising that the very idea of a referendum would provoke the ire of the eurozone authorities. Unlike the European Union, which has a different history, the eurozone project has become a fundamentally anti-democratic project." (Via)