As of late there has been an animated discussion in the public sphere about the importance of free speech, and what, if any, restrictions should be put on speech. While this is an extremely important debate, I think its also looking at the parameters of the debate itself.
One of the most-oft used arguments by those who support free speech is that any laws passed to design "bad" speech (however "bad" is defined, ie hateful, racist, offensive, ect) will inevitably be turned around to suppress "good" speech, which would ultimately be counterproductive to the goals of those who favor restricting "bad" speech. While this argument is compelling and grounded in history, I would suggest it is not the only, and perhaps not even the most important, argument in favor of free speech.
What is lost in this argument is the matter of principle. To many (myself included), principles are far more important than policy. This is a philosophy not limited to free speech. For example, many people are against stealing. They don't oppose stealing simply because they are afraid that others would steal from them, they are against stealing - taking what does not belong to them - on principle.
Free speech is a principle. The ability for individuals to express themselves without threat of violent repercussion is the cornerstone of a free society. Absent this absolute right, there is no freedom, only despotism. When any group of people can decide, at the point of a gun, what the parameters of debate may be you no longer have a free society, no matter how offensive or "bad" the banned speech is.
Many deride the idea of "more speech" as not being a cure for "bad" speech. That's true - more speech is not a cure, but better speech is. Spreading good ideas and principles through free speech, education, and empathy to those people who are misguided and alienated is the only way to deal with hatred in a free society. Those who advocate using threats of violence, whether at the hands of the mob or of government agents, to deal with "bad" speech are no better than the people they decry.