He's right. We have to learn how to manage better.
I, like many managers, worked in my discipline (software test) and was promoted up to being a lead, then to being a manager. This makes me a technical manager; I understood the discipline of test very well. I understood the discipline of management rather less well.
Fortunately, I've learned a lot since I was first a manager. The single biggest lesson:
Manage people, not roles.
If I'm a Test Manager, there's a tendency to read it exactly that way: test first, manager second. When this happens, it's easy to approach every problem as a test problem. After all, test is the comfort zone, and manager is the new and slightly mysterious stuff. Things like team makeup become a matter of "ensuring coverage" by hiring different types. Things like correcting a team members behavior become "logging a bug" and "verifying the fix", which often translates to saying, "here's a problem. Let me know when you've fixed it." That might work when logging a bug for dev, but it isn't likely to work when you're dealing with someone who is frequently late on deadlines.
The better way is to realize that a Test Manager is a manager first. You happen to manage people who test. A Development Manager is a manager first, too; she just happens to manage people who develop. I'll give you three guesses what an Engineering Manager is first!
I don't manage testers. I manage people who happen to test for a living. People have different quirks than tests do. People need reinforcement and guidance and praise and correction and freedom to fail and encouragement to learn and a chance to succeed. This is true for developers, for testers, for support engineers, and probably for accountants and writers, too. (I'm guessing on those last two, but it seems reasonable).
My first responsibility is to the people who need to get the testing done, not to the tests that the people have to do.
If I can get the right people and give them the right environment, the testing will fall from there. Don't worry about the roles. Worry about the people. Get that right and everything else will follow.