I can think of possible reasons. For one there might be a power structure, where employees feel they will harm their colleagues by revealing criticism. For exa

I can think of possible reasons. For one there might be a power structure, where employees feel they will harm their colleagues by revealing criticism. For example if performance is used to determine further compensation and job security. If instead there is a healthy error culture, while improvement and ownership is incentivized, then people might want to share more. Secondly it is bad form to criticize others indirectly, good form to own up your own mistakes or to personally and directly ask for criticism. If there is a middleman, then providing criticism can come off as weak and finger pointing. It might be easier and more healthy to give people an opportunity to ask others about their opinion. Third, they might be many other social reasons like being timid or not thinking all too much about other people's performance. They might just like each other, be indifferent or afraid or what have you. Some might not even know very well how to give constructive, useful criticism. To get people to care and share their opinions freely you need regular practice. Face to face. And again, it should typically start with self-criticism, because that invites ownership and openness instead of a you vs me kind of deal.