Inciting violence is unlawful, "hate speech" is not. What is "hate speech"? What are "assault weapons"?
The right to self-defense is non-negotiable, like someone already pointed out. You can use a car to ram into a sidewalk full of civilians. Should we ban cars?
Or maybe we can actually focus on why there are more people that are causing these mass shootings. If guns are the cause, why didn't we have mass shootings 50 years ago? Guns were even less regulated then.
>Or maybe we can actually focus on why there are more people that are causing these mass shooting
What if the answer comes back to the shortened distance between speech and action caused by certain kinds of speech via the Internet or other channels? Similarly, simply saying a right is "non-negotiable" does not make it so. In fact, all of the rights enumerated by most constitutions of the world are negotiable via parliamentary processes. Is there any reason why the right to self-defense or the right to (almost) unfettered freedom of speech are non-negotiable, but other rights (such as the sale and possession of alcohol) historically have been?
Not to mention that the US has negotiated several times on freedom of speech (child pornography laws, strengthened laws against assault and threats) and on the limits of self-defense.
Besides, there is a vast academic literature (in the fields of first amendment jurisprudence and philosophy) on whether freedom of speech is negotiable. In fact, some scholars have even found existing justifications for the primacy of freedom of speech, or a particular right to freedom of speech (as opposed to the "freedom of action" we implicitly have), such as its claimed inherent value in truth-finding or its claimed importance in the democratic process to be lacking, or even non-existent (for example, see Susan Brison's arguments).
Every right granted by a legal document, no matter how highly regarded, should be and in almost all cases is negotiable. To say otherwise would be, in the words of J.S. Mill, to cling to dead dogma.
I'm not sure what you mean by shortened distance between speech and action. I know it doesn't make it so legally, I suppose I should have said 'in my opinion, these are non-negotiable'. As far as why, I think that it's because this is what separates us from other countries. There's plenty of things the US has done wrong int he past, but the Bill of Rights isn't one of them.