I don't feel there are many "unsayable" things in Austria and Germany. We still have a vibrant right wing here and the left wing is arguably more left than most things found in the US. They just are not allowed to display Nazi insignia.

In fact when it comes to sexuality and nudity europe feels a ton more free than the US when it comes to speech. We don't think a depiction of a female nipple that kids used to suck as kids will corrupt society for some weird religous reason for example. The US is incredibly prude and in that area censorship is rampant, yet nearly nobody complains here.

There is always soft censorship going on in any society — it is just not visible to those inside it if the big majority agrees. You don't need a central, authoritarian censorship for this you need people that have a common shared minimum standard of what they think is acceptable. Or aa you called it: enough "mental defenses"