Why Red Teams Can't Answer Defenders' Most Important Questions
Red-team assessments aren't very good at validating that defenses are working, so defenders don't have a realistic sense of how strong their defenses are.
Discussion
They obviously interviewed some red teams that have a very narrow mode of operation. The red teams I have been part of test individual controls and then try to chain them together for maximum impact.
It's part of setting up the engagement. People seldom want a zero knowledge, outside in approach. It's a waste of money. So I guess if you say this is the only approach a red team can take, then sure, I agree with the article.