I think I agree that IoC in dynamic languages are silly. I also think that if you're doing a project that may require IoC with a dynamic language, then you've picked the wrong language.

Dynamic languages, to me, are domain specific and should be used minimally. I've spoken of this before but strong-typed languages give you well-contracted designs and can be the most explicit about the usage of the code.

Dynamic languages have their usages (i.e., quick and dirty projects, using them to write tests) but shouldn't be used for heavy lifting where an IoC container would live.