Germany has many laws which are different that e.g. the USA. In particular, in the US certain sentiments which are politically and socially radioactive are protected by the US Constitution and the laws, traditions, and expectations of the American polity. Germany is similar in some regards but there is one particular politically and socially radioactive statement you could make -- support for the Nazi Party -- which, owing to the laws, traditions, and expectations of the Germany polity, will result in the government coming down on you like a ton of bricks.