If you never say anything challenging you will never need to have your speech protected. Many people have been persecuted and have died to bring us this amazing gift that allows a scientist to question the common held beliefs that the Earth is the center of the universe and not be burned at the stake.
Freedom of speech is for the speech which challenges the status quo. It is absolute because if you deny your enemies their free speech, when they eventually come to power they will remember and remove your rights, and no one will defend you because you sold them down the river.
Karma is a merciless, unforgiving bitch!