It's not necessarily that I wish to add more limitations. Seriously, can you point to a single place where I said "saying X should be illegal," because although I did voice my distaste for racial slurs and my belief that they do absolutely nothing to further any type of constructive discourse I don't believe I've said that they should be made illegal. However, I do think that in all things we should occasionally take the time to ask ourselves and seriously consider whether or not we should simply be staying the course.
To whit, you said:
Furthermore, the right to free speech is intended to promote the debate of ideas. It is not intended to encourage the dehumanization of people, which is the point of racial slurs and hate speech.
While engaged in replying to how you view civil liberties. That's a clear statement that you do not think the 1st Amendment covers the dehumanization of people or racial slurs and hate speech. It's a little late to start backing down and saying 'but I never said it should be illegal' when you said was that you didn't think such things should be protected by law. If you think they shouldn't be illegal and that they shouldn't be protected under law, I'm extremely unclear as to what's left. Could you illuminate the middle ground there?
While that's good it doesn't mean that some additional restrictions may not be warranted at some point. That's why we need the periodic evaluation that I mentioned above.
You were born in the wrong time. Brandeis and you would be bosom buddies. By the by, Brandeis was on the same court as the 'fire in a crowded theater' Holmes mentioned earlier, and joined Holmes in the unanimous decision that quote is part of to incarcerate some guys that said out loud that the draft was a bad thing. You see, it was considered very unpopular at the time, even offensive, to question the war effort in Europe, so they took a periodic evaluation, applied the current beliefs, and whammo, questioning the draft is jailable. Brandeis in particular said almost exactly what you just said -- that rights should be reconsidered at times to adjust for current society. You're in good company.
Also, it bears mentioning that being "offensive" is already illegal in some regards. Recall Carlin's seven words you can't say on TV. If you drop an MF in primetime TV on some channels you can expect a visit from the FCC who will hand you a hefty fine. Like all things, that bears re-evaluating periodically.
You can say those words on TV, you can't say them over government owed and licensed broadcast frequencies. You're confusing the government placing restrictions on the use of it's property with free speech. The government has some limited rights to curtail speech in some ways when it's done with government held assets. Much like it was recently determined that Texas didn't have to create a Confederate flag license plate, despite the requisite forms and money being provided, because speech on licence plates can be inferred to be government approved and Texas is under no obligation to approve of speech. However, in a similar kind of case, New York got slapped hard for restricting the advertising on the sides of busses by content, where the ruling is that since it's obvious it's advertising space, not government speech, they cannot restrict speech there based on content. They can restrict things like profanity, which is content neutral (ie, it doesn't matter what you're saying, you can't use profanity to say it, so the underlying content isn't evaluated), which is much the same jurispurdence that allows the US to restrict speech on licensed broadcast frequencies based on content-neutral rules like no profanity.
Switch to a cable channel and note that profanity is quite acceptable there. They are leasing that from the government, so the government can't restrict their speech.
It would be interesting if you'd stop and look at what you're going to say before you let go with another censorious statement unintentionally. I say unintentionally because I'm giving you the benefit of the doubt that you just aren't aware of these things.