I don't think the author has any such confusion. He talks about testing to emphasize that he is strongly in favor of testing, but he found TDD as a development

I don't think the author has any such confusion. He talks about testing to emphasize that he is strongly in favor of testing, but he found TDD as a development model lacking. He may be a bit slopping in using "the testing world" when he means "advocates of TDD", but his specific claim is that TDD makes it harder to explore design possibilities than the alternative of what he calls exploratory coding.