Everyone has the right to freedom of opinion and expression; this right includes freedom to hold opinions without interference and to seek, receive and impart information and ideas through any media and regardless of frontiers.
As John Stuart Mill pointed out, the free exchange of ideas is important to any society. The more the more the merrier. They are not all created equal, some ideas are really bad, but we still want to hear them, if for no other reason that we can then point out where they fail. Freedom of expression allows us to try new beliefs on for size and see if they fit our society. That reason alone should be enough to recognize the importance of Article 19 and the similar protections in the US Constitution. However there is other cause to do so.
Our opinions are one of the most basic things that make us us. To deny someone the right to express those opinions is denying them status as a human being. Without voice people are just meat machines doing their work and completing life’s mundane (if sometimes joyful) tasks. I can think of no oppression more cruel than to tell someone they cannot speak their own mind or conscience.
It is a cruelty visited upon the world’s people many times by their leaders. Even here, in the United States we have our politicians have passed laws unduly limiting speach and some attempt to outlaw entire lines of thought. I say this not to beat up on my homeland. Indeed, the scary part is the United States, even today, does far better in de jure respect for freedom of expression (if not de facto through media controlled by the monied elite.) Unwilling to accept any challenge to their authority, tyrants turn neighbors into spies and children into informants. Even in the privacy of their own homes, many throughout the world still do not enjoy the right of their own opinion.
Sadly it is a right too many are willing to abdicate regardless of where they live. Too many want to outlaw offensive speech while claiming to be for freedom of speech, utterly unaware that inoffensive speech needs no protection. They believe only those unlike them will have their rights taken away, which is amazing because history has proven, again and again, that it is only a matter of time until those that have been given the power to silence some, seek to silence everyone. It has shown over and over that even when those in oppressive regimes are trying to behave it is too easy to for them to accidentally offend those in power and end up in jail or worse.
Freedom of expression is the first freedom. The one from which all others spring. Without it, we have nothing.