We're not really talking about people using words incorrectly. If I talk about capitalism as the collective ownership of the means of production and distribution, why then I am clearly misusing the word. No, what I'm talking about here is that the meaning of a word is not so precise as a dictionary definition. A Marxist might talk about capitalism meaning the oppression of the workers by the owners and I might talk about it as the free market and a dictionary won't settle who's right and who's wrong because we're both being meaningful within the contexts we speak. Given that, I do agree that "Clear, concise communication is essential to the efficient functioning of society." We have as speakers a responsibility to see out ideas communicated. Someone insisting they are right in an argument because a word means just what he says it does, is not really communicating.