Ok so here's a bigger picture of what led to the shut down.
1) The ERT (National Radio) was a way for decades for the goverment to reward supporters with well-payed tenured jobs.
2) As a result, there are hundreds of people working there who get payed for menial tasks.
3) The Troika has demanded that about 2500 people working for the public sector will be fired before the end of June. 150.000 before the end of 2014.
4) A large privatisation programme that was a requirement from the Troika to continue the Greek bail out failed on Monday (http://www.guardian.co.uk/business/2013/jun/10/greek-gas-supplier-selloff-gazprom )
As a result shutting down ERT hits two birds with one stone: It allows them to fire more than the minimum 2500 that was required, and also distracts the public opinion from mondays failure that is sure to bring more austerity measures. The goverment claims that the shutdown was justified because of the corruption and thriftlessness of the organization, while the governing party was the one that helped create them.