Inaccuracy over popularity?

A reader wrote in to comment about Mr Devan's column on the English language. His focus was on the words "enormousness" and "enormity". Both mean very big in a noun form but the correct term is the latter. The reader argues that since they have the same meaning and both are accepted in society, there should be no difference in the term used. I beg to differ. If we use a certain ungrammatical/improper/inaccurate term or slang just because everyone else uses it, we are mauling the English language and depriving it of its true beauty.