I agree that they do need to practice what they preach. But they are a private organization, not a government one.
I can no more insist that they allow their members to criticize them in public than I can insist the boy scouts change their recruiting policies.
I understand your position and I actually agree with it. However when you support their right to do this you could also demand that they practice what they preach. Absent that opposition demand they will simply see you as supporting them.
Kinda like giving them a free pass. Just a thought.
Although we cannot legally force them to allow their members to criticize them in public (indeed, they may run their organization as they see fit), we can nonetheless use our freedom of speech to call them on their double standard.