If managers are hired only because they're experts at managing humans, then they're inadequate for the role of managing a dev team. These guys are not just managing people, they're managing processes that they have to know something about to manage effectively.
You can't expect managers to have the same level of technical expertise as the people they are managing. In your view of the world, specialization doesn't exist.
I'm not saying i expect that at all. I'm saying they should have some knowledge about what they are managing than just being a people person. Wouldn't you hate your direct manager having no clue what a code review is? What scrum is? How features are estimated? How estimates can be widely inaccurate? What tech debt is and why it should not be swept under the rug?
