Fact is the First Amendment applies to the government.
It states
Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the Government for a redress of grievances.<1>
http://en.wikipedia.org/wiki/First_Amendment_to_the_United_States_ConstitutionGenerally, unless there is some other law or some state provision that applies to private companies, the First Amendment doesn't prevent employers from firing you for exercising your free speech rights.
Now, used to be that in Germany, private persons had to respect free speech rights except as to certain hate speech (NAZI speech, anyone?) I don't know whether Germans still have that right.
Basically, employees in our country have very few rights. We have at-will employment, for example. Employment rights in our country are really few and far between. We are in bad shape here. Thank Republicans and right-wing Democrats for that.
Americans are isolated. We travel a lot, but we don't learn much as we travel because -- Americans are too lazy to learn to speak foreign languages. Shame on us. (I speak two foreign languages and can read a third. It's not that hard to learn. Try it. You'll be surprised what you learn.)
So, if Americans do not have basic rights like a reasonable amount of free speech in and out of the workplace, they have only their own laziness, ignorance and unwillingness to demand them to blame.