Broadcasting to Politicians' Service

In an outrageous act became reality what was expected but journalists and constitutional law exports and many more hoped to prevent: The conservative majority of the board of the public broadcaster ZDF denied extending the contract of chief editor Nikolaus Brender. The board clearly overstepped its competencies since it's not responsible for staffing while the general director Markus Schächter supported his chief editor.

The conservative politicians do not even have a guilty conscience and consider the decision a normal process. Their understanding of separation of powers is totally flawed:

Jahrelang haben in der Tendenz CDU und CSU Wahlen gewonnen, nicht jedoch die SPD - das müsse sich doch im ZDF ausdrücken.
-- In the last years [the conservative parties] CDU and CSU have won the elections while the [left-leaning] SPD has not - this needs to be reflected in the ZDF.

On questions why politicians can choose "their" journalists the chairman of the board, populist and Minister President of Hesse Roland Koch (CDU) asks the counter-question:

Und dass Bischöfe diejenigen aussuchen, die über sie Bericht erstatten, damit haben Sie keine Probleme?
-- Why aren't you concerned about bishops choosing their journalists?

In his arrogance he ignores the fact that the church does not have executive power while it is part of the society - in contrary to politicians. The independence of the ZDF is now questioned of course. The comparison to Italian public broadcasting RAI where Silvio Berlusconi installed suitable journalists is legitimate. Unfortunately, just like Berlusconi, Roland Koch also gets elected repeatedly and despite all the scandals.

I can see only one positive aspect: A constitutional challenge might end the politician's influence on the board. It only takes one third of the members of the Deutscher Bundestag to vote for it. But when a politician of the SPD already speaks out against such a case since it might do harm to the ZDF I get angry. What can be worse than a public broadcasting service without independence from politicians?