Free speech and hate speech, or: The obligatory Michelle Shocked post

Michelle Shocked has the right to be Princess Clara on the subject of same-sex marriage and then to backpedal furiously when called on it. Concert-goers have the right not to support her, as do performance venues in the absence of a contractual obligation to do so.
People have responded to Shocked in ways like this:

Freedom of speech and artistic expression are critically important, but this isn't free speech. This is hate speech.

In fairness, the petition calls for voluntary measures rather than government censorship. Yet in making the distinction between free speech and hate speech as though they were mutually exclusive categories, which, at least in the US, they are not, the author of the petition plays a dangerous game. For one thing, our opponents have become adept at playing the hate-speech card whenever anyone dares to examine their beliefs critically.