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?