You do have to draw a distinction between compounding, where joined words gain their own meaning (some English examples: breakfast, football, highlight), and ag

You do have to draw a distinction between compounding, where joined words gain their own meaning (some English examples: breakfast, football, highlight), and agglutination, which is the habit of the language to join words together, not necessarily creating a novel word that has its own meaning and dictionary entry, which is what Mr Twain is grumbling about in the article.