Freedom of expression never means that other are not free to voice their dislike of certain opinions. And while some expression is frowned upon other members of the public you are still within your legal rights to express them. The line you can not cross is incitement of violence, denial of the holocaust, breaking NDAs and so on. Contrary to what many Americans think, Germany is not a oppressive country that censors you left and right, but actually has relatively similar free speach rights to the US or other western countries.