Like OP, I was told that I was interviewing for a managerial position (in my case, a PM in SRE) but was given a technical interview that seemed designed for recent grads (I had about 10 years of experience at that point). My interviewer was < 6 months out of a grad program and seemed to have very little context for functional or programmatic management and mostly asked me a bunch of big O and algorithm questions. I was doing pretty well until I had the audacity to suggest that maybe the Google Docs/Drive/Whatever needed to be better integrated at the time.
My sense was that they were looking for extremely pedantic and detail-oriented programmers and nothing that I was being asked had to do with real problem solving, design, abstract thinking, or interpersonal skills.
Not rocket science, everybody. Who knew that people don't respond well to being criticized by strangers! Nobel Prize.
We also do check for negativity in candidates though to balance this. Critical feedback can be given effectively without needing to be rude or unpleasant.
I could tell they weren't used to ever being criticized, pointing out how the interview process had effectively zero behavioral aspects or problem solving questions, as well as all the gaps between one of their products and the competition, and they did not give me an offer.
The funny part is they incorporated much of my feedback into Google Finance years later. It's still a mess, but hey at least they made some progress.