Media snub is no solution
When a political party decides to boycott a specific media outlet for whatever reason, it doesn't really achieve anything tangible.
Here in Greece, such practices were started by SYRIZA and other similar forces, but media boycotts happen all over the world, called for by all sorts of parties when they don't like what they see or hear on the news or on political talk shows.
Regardless of the reasons, it is an undemocratic practice.
In the case of Greek state broadcaster ERT, the main conservative opposition New Democracy party was right to complain about the way that many of its commentators only sing one tune, and its obvious pro-government bent, but banning its politicians from appearing on or speaking to the national television and radio broadcaster is not the answer.