If you read the article you would understand how there's nothing improper about the usage. If you knew anything about human language you'd know that there's no such thing as an improper usage. Sheidlower is a highly respected lexicographer and his entire article subtly acknowledges this fact. The speech community uses the word in a certain way, and all who hear it understand what is being said, without even consciously realizing it. There is nothing improper or wrong about how it is being used. The amazing richness of language is due in part exactly to the kind of mechanisms that cause drift such as seen with 'literally', and it's a testament to the endless versatility of the language mechanism. On the surface at which the average person contemplates it, sitting around in their armchair, language is not a rigid, logical artifice that makes the sort of naive sense they want it to.
Read Pinker's 'The Language Instinct' for a good discussion of the topic of language mavens. My pet peeve is people like you, who have pet peeves that are grounded in your own ignorance.