After reading the history of this article, it appears that the assumption is that templates cannot be used for duck-typing. By my understanding, duck typing does not necessarily imply dynamic typing or runtime checks, so templates can be used (among other things) to duck-type code. The classic example here would be the C++ algorithms, which are duck-typed for iterators.
If there is a central authority that defines duck-typing to exclude static checking, it should be referenced by the article.