The only reasoning that I can come up with for the inclusion of a confidentiality clause is to prevent others from knowing about, or being encouraged to also make a claim.
This is a despicable and deliberate attempt to prevent genuine, valid claims from being made in the first place. I hope the CAA or other NEB is prepared to do something about it, as this would fly in the face of both the spirit and intention of the regulations.
There may be some rare occasions when an airline has a particular reason for requiring a confidentiality clause following a court hearing. Although I cannot think of a practical reason when this could be so.
However, I believe that to use it as a blanket practice in all or even most CEDR cases would probably equate to a restrictive practice.
If an NEB did consider this to be a restrictive practice, they could take action against the airline. Particularly if other airlines also suddenly start to include confidentiality clauses upon claimants who have successfully defended a claim via CEDR or other adjudicator.
As mentioned before, there is some evidence just beginning to emerge that this may be the case, as BA is not the only airline to have very recently begun this practice. It's too early to tell at the moment, but it's a situation that needs monitoring.
Hopefully all fair minded claimants will resist this practice and see it for what it is.