They then enter an environment where the group isn't ad-hoc, meaning there's a hierarchy and people, especially new CS grads, get overruled. They're expected to comply with policies and processes that they had no input into. And they're expected to write code that doesn't just work, but is understandable and maintainable by every member of the team.

I find that most new grads are very able to come up to speed on the code and the structure of our project. This likely comes from having a very malleable mind and never having seen a well-organized codebase. But it takes a good two months of almost constant corrections before they're contributing to the team in the right way and many more years before the understand why that type of contribution is necessary. Teamwork is more than just not writing the entire project yourself and it feels like CS grads are never taught any of the skills necessary to collaborate in the real world.