I suppose what is maddening about it all is that, in one sentence they’re wagging their fingers at Christian counselors for rejecting sufficiency, but in the next sentence they’re functionally adopting the very position they were just criticizing (I think because they intuitively know it’s an absurd and unlivable position)!

To continue this comparison, I relate biblical counseling to presuppositionalism whereas integrationist counseling is related to evidentialism. The problem with evidentialism is not that they use evidences, but that they begin by assuming a neutral starting point through which to assess and evaluate the evidence. Unfortunately, since there is no neutral ground between those who are in Christ and those who are in Adam, evidentialism begins by granting unbelieving presuppositions in their defense of the Christian faith. In a similar way, integrationist counseling does not recognize the inherent antithesis or opposition between believers and unbelievers. As a result, biblical counseling counters integrationist counseling by beginning with a biblical worldview.

So the question is not about the benefit of “science and observation” (steps 3-5), but the presuppositions and supposed neutrality of secular science and observation (steps 1-2). I think this difference is found when Lambert says “biblical counselors do not rely to any degree on the counseling insights of secular people.” The key word here is “rely,” to depend on or to trust in secular counseling. This is different than maintaining that one approach “accepts secular sources whereas the other never does.” With this in mind, I think that you are setting up a contradiction in the biblical counseling approach that is not there.