I think saying 'a terrible work environment' is a bit of a stretch. The important part of criticism is that it's taken constructively - often it's best done between peers, but sometimes it's best done with (good) managers.
I think a key issue is that coworkers can be awesome workers, but HORRIBLE at critique. It's a skill that people aren't always good at. I know I could be better. A good manager will be great at this, and it's often best to let the best person at this do the talking. Managers can also be great as go betweens, and councillors for both sides, so that hatchets don't get buried directly into coworker skulls.
That said, the best teams manage themselves.
