“James clearly teaches us that we must “confess our sins to one another,” not just privately to God.”
No. In this passage the confession is to one you’ve sinned against.
“James 5:16 must be read in the context of James 5:14-15, which is referring to the healing power (both physical and spiritual) of the priests of the Church.”
No priests mentioned here. No priests listed as a church office in the NT.
“Hence, when James says “therefore” in verse 16, he must be referring to the men he was writing about in verses 14 and 15 – these men are the ordained priests of the Church, to whom we must confess our sins.”
No ordination mentioned either. Nor priests. If it were true that sin should be confessed to the elders mentioned earlier, he would have said to confess your sins to the elders instead of “to one another”.
He did not.
1. James had just told us to go to the presbyter in verse 14 for healing and the forgiveness of sins. Then, verse 16 begins with the word therefore—a conjunction connecting verse 16 back to verses 14 and 15. The context seems to point to the "elder" as the one to whom we confess our sins.
2. Ephesians 5:21 employed this same phrase, "to one another," in the context of teaching about the sacrament of holy matrimony: "Be subject to one another out of reverence for Christ." Even though the text says "to one another," the context limits the scope of the meaning of "to one another" specifically to a man and wife—not just anyone. Similarly, the context of James 5 bears out that the confession "to one another" refers to the relationship between "anyone" and specifically an "elder" or "priest" (Gk. presbuteros).
3. The final words of the passage speak specifically of ministers called by God to minister to his people in his place, i.e., Elijah the prophet (cf. Jas 5:17).