JS is very cool because of how readily available it is and the awesome ecosystem that has grown around it. That said - you don't have to be a CS professor to see that the language (especially in early incarnations) wasn't well designed, to put it nicely. A.H. knows this just like anyone with the skills to design languages and compilers.
Haha, I met him on a JS conf once. There was one of those old "JavaScript has no types and is no real language" guys and he kicked his ass.
Basically he said static typing could be good and there were languages like Scala out there with real good type systems, but most of the "pro static types"-fanboys are using crap like Java or C++.