I think the point is to defend speech even when you don't like it. That's the only way free speech exists. Any attempt at judgment over what sort of speech is legitimate or acceptable immediately negates freedom of speech and curtails the ability to think. Humans are not equipped to make such judgments without bias and emotion, so free speech absolutism is what guarantees our ability to be free to think what we want, and not end up in a tyranny of thought police. No one ever bans inoffensive speech, so the purpose of freedom of speech is to stop those who find anything offensive from shutting it down. Historically this has been championed as a central freedom of America and one of the reasons we put up with no social safety net (which is another topic and makes no sense to me), but recent generations seem to have forgotten.