Freedom has always been treasured as an idea, even as its substantive content has differed from one legal culture to another and its very meaning has been a battleground between left and right. Plato was famously against freedom of speech for poets, and that Platonic strain in Western thought is still there to be found. Anyone who thinks, like Plato, that they have grabbed hold of the key to virtue is unlikely to value freedom of speech -- that was the history of religious attacks on freedom in the medieval period in the West and the current story in much of the lands of Islam today.

Freedom of speech (the Bill of Rights mentions "the freedom of speech," suggesting a concept of known contours and limits) is more of an American thing. It's not much in evidence in Canada or the UK as a fundamental value, certainly not in the same sense as it is here, and even less so in the EU.

The American idea is freedom as an attribute of individuals, both a 'freedom from' and a 'freedom to'. That's always had plenty of enemies and few friends among those in charge even in the US. Lefties, who usually see individuals primarily as members of larger groups, regard the group as the more important focus of attention. Conservatives look at the same thing, and consider groups to be aggregations of autonomous individuals. Life, being a messy thing, doesn't fit easily into either paradigm.

Humility, a recognition of one's own limitations and fallibilty, is the characteristic that is likely to make someone treasure the American idea of freedom of speech. Those who have all the answers are morely likely to think that they should dominate the conversation, even (if necessary) to drown out competing voices. No wonder freedom of speech is not much treasured, except as a slogan, on American campuses today.