According to J.S. Mill, free speech should only be constrained to the extent that it violates what he calls the harm principle:
"The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others."
He makes a distinction between causing harm and causing offense. Revulsion, disgust, psychologically upsetting speech, discriminatory speech, insults and so forth fall under the latter category. Free speech which merely causes offense should not be prohibited according to Mill however controversial or contrary to social norms such speech is.
But how strong the definition of the "harm principle" should be is subject to debate.
Contrast for instance, screaming "Fire!!" in a theater - which might cause injury and death from a crowd stampede - with "All <insert_ethnic_group> are inherently inferior to <insert_other_ethnic_group>".
The difference between causing harm and offense is that harm is universally injurious, whereas as what causes offense is only experienced subjectively.
Although I find blatant hate speech detestable, there is a worrying trend where a majority of people consider hate speech to mean "anything that we disagree with". In our times, it is difficult to speak frankly or be a contrarian without being demonized. And this is precisely what J.S. Mill calls "tyranny of the majority" and consequentially what leads to loss of individuality in society.
We should also recognise that the reasonable apprehension of harm is often an allowable basis for an action in law. For example, to assault someone is to present them with a clear threat of harm, whereas battery is to actually carry through with the harm.
Defamation (libel, slander) is recognised to be a problem for a similar reason. If someone presents misleading and disparaging things about me to the public, of course people are free not to believe it and it may be that nothing will happen; but I very reasonably fear damage to my career and social status. We recognise defamation as a crime even when no harm has been demonstrated to occur.
Does hate speech cause harm? Not directly, since sticks and stones may break my bones but words can never hurt me. Like defamation, however, it can mislead to a point where people reasonably expect injury to their career or social standing; and like assault, it can constitute a threat of bodily or other harm. Many of the people who push agendas of hatred are little interested in the outcome of the democratic process or in dialogue with the people they hate — they just want those people excluded (or deported or worse).
We live in a time, unfortunately, where we aren’t all working together with a good solid understanding of “public dialogue”, “harm” and “the threat of harm”.
People feeling bad is not harm; but often that is close by. The absence of injury does not mean we can ignore the possibility of it.
On the other hand, though, if we can’t see a concrete harm that (a) has occurred or (b) is clearly in the offing — if all there is, is some hurt feelings — then a restriction of speech would constitute an offence against a person’s rights.
"All <insert_ethnic_group> are inherently inferior to <insert_other_ethnic_group>"
It seems you understand the correct answer in accordance with Mill, but then willfully choose to ignore that answer since it differs with your personal value system.
To be very direct, hate speech does not violate the harm principle in the same immediacy or capacity as does yelling FIRE! in a crowded theater.
Fortunately, courts in the US do not have trouble discerning this difference.
If J.S. Mill were here right now, he might concede that it is hard to find philosophical justification to treat the crime of yelling "FIRE" in a crowded movie theater differently than the crime of yelling "FIRE" in a crowded movie theater with the intent of killing people of a specific ethnic background...
No writer in the 19th century could have conceived of what "speech" would mean 150 years later in the context of instant worldwide communication. But Mill would not have trouble classifying the expression of certain opinions in certain contexts as causing harm. There is no major logical twist required to "infringe" on liberty in the case of hate speech, and remain consistent with Mill's writings.
That completely ignores many of the concepts addressed in chapter 2. If you have to discern harm from context and then use that to classify speech in such a way that it can (or could be) silenced you are violating liberty, according to Mill. Harmful speech is not the same as offensive speech. The difference is the cause of injury. Does the speech itself produce the injury or does it manifest derivative responses that are injurious, such as a fist punch?
> If J.S. Mill were here right now, he might concede that it is hard to find philosophical justification to treat the crime of yelling "FIRE" in a crowded movie theater differently than the crime of yelling "FIRE" in a crowded movie theater with the intent of killing people of a specific ethnic background...
Not relevant. The intent is to kill people either way.
> But Mill would not have trouble classifying the expression of certain opinions in certain contexts as causing harm.
Mill's writing absolutely disagrees with this. Read chapter 4. He provides specific examples.
Exactly, when there was always intent to harm, it is easy to see how speech causes harm.
> The difference is the cause of injury. Does the speech itself produce the injury or does it manifest derivative responses that are injurious, such as a fist punch?
You are contradicting yourself. The word "FIRE" isn't causing direct injury, it manifests derivative responses that involve people getting hurt.
> Mill's writing absolutely disagrees with this. Read chapter 4. He provides specific examples.
Okay, I re-read chapter 4. None of the examples justify this reading. Mill is far more focused on private behavior than public speech in that chapter. He thinks polygamy is bad because it subjugates women, but at the time Mormons literally fled the country to the Utah desert, so he has a hard time justifying why an American would call for interference with the ostensibly consensual polygamy of the early Mormon Church.
Nowhere does Mill suggest that speech can't cause harm.
Does that claim apply to itself? I.e., what if I were to claim the negation of that?
This is a pretty solid argument for freedom of speech in the sense in which it is generally protected: as something that contributes to public dialogue in politics, the sciences and the arts.
Many things seem to be this but aren’t. Hate speech is not an opinion in this sense: it is not something presented as an argument or topic for discussion. You are either with the haters, or you are against them. Whether something is political speech or not depends very much on how it is offered to the public. The same idea — memory safety is a recent, innocuous example from this forum — can be a rallying cry for some and a point of discussion for others.