I agree with this, but the social dynamic just sucks. I would much rather the manager be part of the team, not feel lonely, be able to joke around about safe things (so, not politics, religion, or identity), and even complain a bit.

You will not get the training you need

This is just plain unacceptable. It is likely due to companies thinking everyone is replaceable and not investing in their employees though. I don't know how companies can simultaneously want managers to practice the sanitized humanity detailed here while also not providing training to do what they want.