Technically no government allows true freedom of speech. In this country God is considered Sovereign and people aren't. So you can never have true freedom no matter what is written down in the Constitution/Bill of Rights, someone can always come along and destroy your political aspirations if you dare speak out. Even Thomas Jefferson was called the "Godless Atheist" by his political opponents.
So free speech is really about who can drown out who, who has the power to control people, either through bribes, or through crushing your ability to seek liberty and happiness, if you don't pay respect to the national deities, the Flag and God. In Roman times it was little different, pay tribute to the Gods or be fed to the lions. Today it's keep your mouth shut when you see the nutters pay tribute to Jesus or risk career suicide, it's more subtle than being lunch for the lions, but no less damaging for those that seek true freedom.