That is so true, even people giving negative feedback have trouble when they get negative feedback from someone else. Therefore I think the system, the site, should make it easier to give positive feedback, than negative.
To you know bring about a positive community feeling. The purpose of the site should be to help its users not to make oneself the over-arbiter of what is correct what is not.
Facebook has its share of problems but excessive unexplained down-votes is not one of them.
This will spread and people will cling on. Soon you will reach self moderation due to the positive nature of the community.
Learning to accept feedback is much about learning that you may actually receive positive feedback and that your self worth is enough.
So I was listening to l to this guy Jim Thuresson which is a mental coach. His life is basically breathing positiviness, and his take on it is, it works, you shoukd do it too. If you fill your head space with 100% positive thoughts there's no room for anything negative. Maybe going on strong here, but it's such an important message. I just winder how we bring that thought onto the Internet.
It's lose/lose. Don't tell them why and they get frustrated, tell them why and they get defensive. It takes a rare user to take the feedback and use it to improve their question.