On the contrary, short names are a source of clarity and expressiveness. Humans convey so much information through context, and shadowing nicely allows us to at least approximate that.
But I would be okay with this stance (yet would not use coffeescript) if the language had a mechanism to warn you when you're trying to reuse a name. Instead the language's features combine in a way that will clobber your code and lead to subtle or not-so-subtle bugs.
