I think he is describing the (common) situation where you want to do TDD for new code, but are dealing with an already existing code-base that doesn't have test coverage and just isn't amenable to testing the way it currently is.
So you can't really do TDD for your new code without refactoring the existing code-base. But refactoring the existing code-base without good test coverage is nasty.
So you can't really do TDD for your new code without refactoring the existing code-base. But refactoring the existing code-base without good test coverage is nasty.