While some sections of the Constitution are difficult to interpret and subject to argument, there seems no difficulty in understanding "Congress [and the states through incorporation] shall make no law ... abridging the freedom of speech". There is no ambiguity or confusion here. However, every so often the courts have carved off new areas of speech as outside the First Amendment's purview, leaving certain types of speech as proscribable at the whim of the states, and sometimes of Congress. Despite protestations to the contrary, this turns a restriction on abridging the freedom of speech into a limited protection of merely a certain type of speech, from a protection of personal freedom into a support to prop up the sort of discourse that continues our social system -- what seperates obscenity from other speech, aside from the court's judgment of which one's content best contributes to, as Justice Scalia says, quoting Chaplinsky, "the social interest in promoting order and morality"? Justice White's concurrence is more honest on this point when he states that if "the content of ... speech is evil" then it is "by definition worthless and undeserving of constitutional protection." And who to judge the speech's evil content but the courts promoting order and morality? This is exactly the sort of content discrimination we are supposed to be protected against.
For this to not be as arbitrary as it would seem, there must be some opposing Constitutional right or principle to rely on, not merely the judges' biases. For example, a prohibition on yelling fire in a crowded theater could come from a right to life, or to not be unnessesarily put at risk. The exception for libel could come from the value of personal autonomy, allowing people to be defined and known by the actions they have freely chosen and not by those harmfully made up by others. The excerpt from Charles Lawrence suggests, as does the assignment, that a possible way to wrest hate speech from First Amendment protection is Equal Protection. In some ways absolute free speech is free the way the free market is free, or the way everything in a libertarian system is free: it's all well and good to protect people from government oppression, and overall the Constitution does this well, but doing so too stringently prevents the government from protecting people from other people's oppression. Perhaps ensuring the ability of some subordinated classes of people to themselves speak and take part in society requires the ability to regulate speech intended to discourage their invovlement. This would rightly be a decision made by state legislatures who are more aware of the local social climate and what tensions need to be addressed, with perhaps the ability of Congress to intercede when necesary, as it did with literacy tests for voting.
Clearly, this alll is open to some of the same arguments already made in the first paragraph -- for example, allowing judges to dredge rights like this, or famously the right to privacy, out of the Constitution invites its own sort of bias. The Lawrence excerpt, for example, argues against "the best ideas [rising] to the top" in an unregulated marketplace of ideas with the example of racists being elected. This assumes racism is an incorrect idea that should properly be defeated by truth. While I personally agree, that is exactly the sort of idea favoratism that the First Amendment protects against; on that, at least, the Justices in R.A.V. all seem to agree. As Scalia makes clear early in R.A.V., there are many other statutes placing a burning cross on someone's lawn violates. There seems no reason to make it an opportunity to carve out new areas of unacceptable speech.