Earlier quoted context omitted.
If that was truly the case, then why do so many engineers complain about having a non-technical manager? Thinking that a manager does not need even a little bit of domain knowledge is something managers tell themselves to feel good about themselves, but it is not actually true. Both the people part _AND_ the technical parts are the hard parts of technical management.
Engineers complain about everything
That has been a divide I've experienced between senior devs and tech leads vs product owners and managers who were not technical. The former tend to be pessimistic and the latter optimistic.
It's easy to say that something that seems simple when explained in simple terms is easy or quick to implement, but the people 'at the coal face' are often all too aware of the implicit complications of the task.