This is an old chestnut. Mathematical notation is terse because mathematics doesn't consist entirely of notation! Look at any book or research paper; you'll find a great deal of text surrounding equations. Comparing this to code is nonsensical. Unless you're reading something in WEB, you are much more likely to encounter code than comments. There are certainly some unfortunate conventions and cruft in mathematics, but every generation of mathematicians rewrites in part what it inherited from its forebears.