The real issue with the ABC is self censorship from right wingers

When I was studying my Bachelor of Arts with a major in Politics a minor in Film, TV and Media Studies I mostly took political papers that crossed over with media.  One of these papers was the Political Content of Television.  While I can't recall all the paper's material I remember that we talked about media gatekeepers and how they influence what is published or broadcast.  This is what's known as Noam Chomsky's Propaganda Model.

For those not familiar with the model there are five parts and five filters:

1 - Ownership
2 - Advertisers
3 - Readers/Flak
4 - Sourcing
5 - Anti Communism

Let's explore each of these filters starting with ownership.  Media ownership determines the content that will be published/broadcast.  Private networks such as Murdoch's News Ltd can have a right wing bias because they are effectively answerable to nobody other than themselves and their investors.  Government owned networks have to be more careful because they're answerable to the public and the Government of the day, so if you have a right wing government it is likely the views will be right wing and the reverse for a left wing government.  Networks will endeavour to keep governments happy as they're the ones paying the bills.

The second gatekeeper are the advertisers.  More often than not when a host on a network says something highly controversial the advertisers will pull their money so the network will bow to pressure to keep their advertisers happy.  Advertisers tend to advertise on networks or in papers/websites with similar views to the company.

Readers and flak are the third gatekeeper and if they don't like what is being broadcast they'll make that very clear using social media or direct complaints to the network.  These complaints could be in the form of writing letters or simply switching off in which case the network would have to make adjustments to keep the readers happy.

Probably the biggest one for journalists is sourcing.  When you're a journalist you try to get opinions from a number of different sources however that isn't always possible, especially when the people you want to talk to won't talk to you.  If you're a network trying to air views from both sides then you can't do that if only one side is willing to talk to you.  It becomes rather difficult so naturally you end up with a right or left wing bias.

The final filter is anti communism.  People are very wary of networks which preach communism.  Many would argue that is all networks.

The Propaganda Model is related to what's going on in Australia right now with publicly owned broadcaster, the ABC.  Right wingers in particular have taken to Twitter to vent their frustrations at their left wing bias.  They conveniently ignore the fact that Prime Minister Tony Abbott, leader of the Liberal Party has issued a ban of front benchers appearing on Q and A.  The only frontbencher to buck this trend is the controversial Communications Minister Malcolm Turnbull who will appear on the program on the 13th of July.  Now it would be well and good to criticise the ABC for their bias if they refused to have right wing panelists on the show but that's not the case at all.  Right wingers are refusing to go on the show which makes it a difficult situation given that the right is effectively closing themselves off from the public and not letting the public hear their views.

It's rather a contradiction that the right complains their views aren't being heard on the ABC and then they effectively self censor.