To some extent, you are correct. However, there are limits. For example, if I use rascial epitaphs, or my intent is to belittle, humiliate or intimidate, then you are not protected.
Fighting words The U.S. Supreme Court ruled in 1942 in Chaplinsky v. New Hampshire that “fighting words”— words “which by their very utterance inflict injury or tend to incite an immediate breach of the peace” — are prohibited and are not protected by the First Amendment. Almost 30 years later in 1971, the high court limited Chaplinsky in Cohen v. California by holding that an individual could not be held criminally liable for wearing a jacket into a courthouse that said “Fuck the Draft.” The Supreme Court distinguished the two by explaining that Cohen’s action was a “simple public display” as opposed to a direct insult or intent to incite harm, as was the case in Chaplinsky.
We agree that you may say anything you like, whenever you like, within these bounds given above - and you are protected. However, where we disagree is the idea you think that you have the right to force others to listen.
Perhaps like "... you stupid ass..." to a frantic 911 caller trying to get an ambulance sent?