I think it comes down to this question:
"Does the government have a moral imperative to enforce free speech, or simply to not stand in the way of it?"
Well that's one of the questions at play and it is good of you to put it on the table. And so it is true that
while governments can violate the principles of free speech by it's actions, governments cannot violate free speech through negligence.
You
The XKCD explanation seems to suggest that people can criticize or protest speech, but governments can't arrest either side.
XKCD does rightly suggest that free speech does not preclude speech from being criticized or protested. And it rightly conveys that free speech entails the government can't arrest folk for the content of their speech (there's exceptions but we can forgive a cartoon for not mentioning this).
Free speech means the government can't arrest you for what you say
You
Under that idea, the government can't force any group or individual to stop speaking, or persecute them on the basis of their speech, but is not responsible for negating the consequences of speech, or for creating free speech for all.
Yes. And it is good of /u/olbertie to raise the Westboro funeral protest example for it puts to rest the fiction that free speech in the US is merely about protecting speech from government interference. The Westboro funeral protest supreme court case illustrates that the US protects speech from interference by other individuals. In this case
the Court held that speech on a public sidewalk, about a public issue, cannot be liable for a tort of emotional distress, even if the speech is found to be "outrageous".
That is, so Westboro continues to be allowed to protest funerals free from the consequence of being sued by other individuals.
olbertie
If you are going to frame this as a moral principle rather than a legal principle the argument could be equally made that people have a moral principle to consider what they say and how they say it.
You can make the argument but it's not very convincing if you mean that a person's moral right to free speech is conditioned on whether their speech is hateful, outrageous, or offensive.
By your reasoning, the moral principle being broken here are the people who are standing up against the protestors from the church.
No. The people standing up against the protestors (the bikers and such) are rightly siding with the law in America to ensure that Westboro Baptist's speech doesn't become an infringement of the speech of the funeral participants.
WBC established that they had complied with all local ordinances and had obeyed police instructions. The picket was held in a location cordoned off by the police, approximately 1000 feet from the church, from which it could be neither seen nor heard. Mr. Snyder testified that, although he glimpsed the tops of the signs from the funeral procession, he did not see their content until he watched a news program on television later that day. [http://en.wikipedia.org/wiki/Snyder_v._Phelps]
And so the US supreme court (and the local ordinance) is rightly preserving Westboro's right to criticize and stopping Westboro from preventing the speech of the funeral goers.
By my reasoning, the moral principle being broken here are the people who are abusing the notion of free speech by spreading hate.
Yours is a common enough sentiment but it renders free speech meaningless. While free speech protects innocuous speech too the only cause for needing the principle of free speech is as a protection from the difficult, controversial, hateful, immoral, outrageous speech. Passing pleasantries about the weather isn't speech that is threatened. Important matters, such as political matters, requires the airing of truths and falsehoods that will be often upsetting to others.
PsychoPhilosopher
I think governments do have a responsibility to ensure that every citizen has the capacity to communicate.
Yes, I think the consequences of a properly protected free speech extend that far.
In Braddon-Mitchell, D. and West, C. (2004), What is Free Speech?. Journal of Political Philosophy, 12: 437–460. doi: 10.1111/j.1467-9760.2004.00208.x, the authors list six requirements for free speech, fully realized. Something like the freedom to:
I can only remember those four. But, for the authors, one of the consequences of this conception of free speech was that it entailed some positive liberties (taking Isiah Berlin's distinction) of the kind you mention ... the provision of eduction and the like so that citizens have the capacity to understand and consider. (That provision is agnostic on whether the positive liberty is instantiated directly by the state or through a free market ... that's a separate debate).
On a separate matter. Free speech being a moral issue not only drives, because it ought drive, the kind of law on free speech we have (and in this way is just an example of a general relationship between morality and law). Free speech is a moral right on a sub legal level.
In a group of friends down the pub your moral right to free speech can be infringed if one in your group consistently interrupts you (without it being desired by you) or hogs the conversation. There ought be no legal consequence for this infringement of your moral right to free speech. It is an infringement nevertheless. Down the pub, it is possible to be immorally thwarted from saying what you want.