Is there any country that protects all speech that you know of?
(Related to the law you mentioned, in Germany they also have laws that are reactions to WWII, and they arrested some Chinese tourists for making Nazi salutes for tourist photos outside a government building last week.)
Protecting speech is often in tension with other individual liberties that are supposed to be protected, and the purpose of government is to arbitrate those disputes. I don't think there are any that grant unfettered protection to speech-- a government that permitted advocation of treason, for instance, probably wouldn't last very long.
It is definitely possible to have complete protection of speech. It's a choice, and the repercussions of it would not involve great harm, although since the 1950s we seem to be getting closer (and sometimes further).
Treason is only possible if a country is at war (ie has an "enemy"). The speech would be protected as it is now (that wouldn't be the crime they break), but they could be found guilty of committing treason by the same (speech in this case) act.
(Related to the law you mentioned, in Germany they also have laws that are reactions to WWII, and they arrested some Chinese tourists for making Nazi salutes for tourist photos outside a government building last week.)