With all respect, I think you are about half right. Words do mean things - yes, about that you are absolutely correct, and thank God, our Constitution, and Jim Robinson for forums like this one where we may intelligently discuss such things. However, the decline of Western Civilization owes its origin to the deconstruction of meaning, language, context, and manners, the font of which has been the elite academic world, not the "street" where vulgarity has always been the preferred form of expression.
But consider that even relatively uneducated people may (and frequently do) express noble ideas, even while doing so in the language of the gutter. In fact, I would far rather expose my ears to an honest four-letter-laced criticism of the moral character of, say, Bill Clinton, than to an erudite but dishonest defense of it.
I cannot fully explain myself here without venturing too deeply into the realm of "Vanity", so I'll just note that my frequent experience has been that the Left uses profanity wildly, angrily, and stupidly, while the Right (Bill Buckley, P.J. O'Rourke, and Tom Wolfe, to name a few representatives) use it in context and appropriate to the occasion. Some "bad" words are quite useful, powerful, and evocative - and are unfortunately overused in a world long on expression and short on meaning.