The fear of litigation was by far the biggest reason we heard, but there were some other popular reasons (mostly relating around conflict avoidance):
* Notably, giving feedback feels like an opening for the candidate to submit a rebuttal instead of ending the conversation (e.g. "You didn't do well on X" "Well here's a list of reasons why I didn't do well, and here's me demonstrating I actually understand X").
* It was just a personality conflict that few people would admit to in writing (e.g. "You're kind of an asshole, I don't want to work with you" isn't something you tell a candidate).
* There just isn't much actionable feedback to give. "Nobody felt excited to potentially work with you" isn't really actionable feedback, and sharing that just feels kinda mean for no reason.
* Someone better came along to fill the role and nobody wants to tell a candidate "We found someone better than you".