I hold meta-ethical subjective relativism, that all of our ethical beliefs are fundamentally subjective: the properties of goodness and badness name only states of mind, not properties of objects outside our minds. Things aren't good and bad in themselves, there are only subjective, mental facts about what people approve and disapprove of.
This position entails then that to the extent that there is such a thing as a social ethic, it comprises more or less complicated statistical properties of individual beliefs. Thus the only way to change social ethics is to change the individual ethical beliefs of a large number of people. And the best way to change individuals' beliefs is by speech (the deprecated alternative is to simply imprison or kill everyone who has or lacks a particular belief).
Therefore speech has an ethical component. Indeed most speech, even speech not intentionally directed at ethical belief (i.e. propaganda), has some sort of ethical component, at the very least indicating some degree of the author's or characters' approval or disapproval of the depicted activities. Even news reports, supposedly purely descriptive, often betray an ethical bias in the language used to describe. It takes considerable discipline even in science to remove ethical biases and only describe the world.
Of course, we should not adopt an overly simplistic evaluation of the moral content of speech, nor a simplistic, over-literal model of how it actually affects its listeners' moral beliefs. But it does appear to be the case that clear societal ethics do emerge from the cacophony of millions of voices.
Ethical criticism of speech is, of course, a form of speech, indeed of propaganda. The recent conflict over Don Imus' racist remarks is a good case in point. It is instructive to note that the conflict played out exactly the way we would expect in a free society. Had CBS/MSNBC been fined by the FCC for Imus' remarks, I would have been quick to object: It is not, nor should it ever be the government's job to regulate speech. The counterargument contains exactly two word: First Amendment. Full stop. The members of society evaluated Imus' remarks as ethically wrong, and, using nothing but social pressure in the form of speech, marginalized his racist content to the point where his sponsors no longer considered it in their interest to amplify his views.
With regard to my previous essay, there are two moral questions: What sort of sexuality do we want people to have, and how do we want people to relate to other? It's difficult to have no opinion: even the opinion that our sexuality and relationships should be left to chance and genetics—and that to tolerate with approval all the sorts relationships that ensue—is a particular opinion; to have no opinion, one would affect no preference at all between ideal anarchy and inflexible totalitarianism.
Consent and personal responsibility, although important, cannot be the end of our ethical discourse. Consent must account for the range of choice; the concept is vacuous in the absence of or severe restriction of choice: A chattel slave "consents" to slavery because he has chosen it over death, and thus takes "personal responsibility" for his choice. Liberty—especially in our society of complex interlocked dependencies—is not just a narrowly negative concept, the absence of physical coercion, it has by tradition and history become, like it or not, both wider and positive: There are other forms of coercion than violence, and we have positive obligations to make available a wider range of options, encourage (and thus define) wise choices and discourage unwise choices.
It's not even that we have real obligations ("obligation" is just a metaphor) so much as that, with six billion of us (and more on the way) crowded on a planet that can support only tens or hundreds of millions without complex technological specialization) we actually do affect each others lives by all our speech, even by our silence. One can escape these obligations only by abandoning empathy, and becoming indifferent to the suffering of others.
 In the broadest sense of communicative behavior, including speaking, writing, pantomime, television, movies, video games, etc.