People also used to program computers with punch-cards. Everyday. Of course they can use Javascript.

You didn't address any of his points though. Where are the great Javascript tools and IDEs? There are tons of them for languages with static typing and classical inheritance.

Here's just one tiny example: Compare how you go about refactoring code (renaming classes, functions, etc) in Javascript with the many ways that it may be done in Java or C#.