I think I'm blithely misreading the article here, but I'm inclined to take it as advice about how to do TDD, rather than an argument against it. Specifically: if a class has lots of tests, this is a sign that the class is too complicated. Refactor until it is simple enough not to require as many tests (possibly by narrowing its interface, possibly by breaking it up into multiple classes, possibly by rethinking how it's implemented).