This is obviously false. For example, plenty of democracies have flourished despite having libraries where silence is golden.
> One could argue, that when you live in a democracy, politics are a necessary duty for every citizen.
HN is international and if I recall correctly, more than half of users are not from the USA. Some users don't live in a democracy and some don't believe in it.
> Some users don't live in a democracy and some don't believe in it.
I look forward to arguing with monarchists about their views at some point in the future, then.
There is a difference between "not allowed to speak" and "not allowed to speak about politics". You can't speak under water, but a pond isn't the proof that democracy can't exist.