This may be controversial, but I’d like to briefly put forward a thesis:
No Christian church or ministry should ever ask a Christian to sign a non-disclosure agreement (or non-disparagement agreement, or any other similar document to the same effect).
You may read that and think, “Okay, but big deal. Which churches or ministries are doing that anyway? Aren’t you tilting at windmills? This sounds a bit like calling on churches not to insist that everyone must eat KFC for lunch on Thursdays.”
But, sadly, NDAs have become all too common in Christian circles.
The most common situation where an NDA may be used (to my knowledge) is where a Christian leader is being accused of ungodly behaviour—spiritual abuse, verbal abuse, bullying, dishonesty, manipulation, and the like—by someone within their church or ministry.