there needs to be at minimum some common language between managers and what they're managing. otherwise it worse than broken telephone.
without a certain level of understanding, it's just a useless abstraction level for the sake of filling a govt position.
But you can be an idiot regardless of experience, and selecting an idiot as minister is arguably the graver error.
They don't. It's a bureaucracy, not a meritocracy. The first business of a bureaucracy is to maintain the bureaucracy, and the second business of a bureaucracy is to reward party loyalty, and the third is for the bureaucrat to maintain and enhance personal power.
He will listen to people of his own social class and party whose word and sponsorship lends political merit, take orders from above, and his subordinates will do as they're told.
We will see it play out in front of us again:
AMD v Intel
That doesn't mean this particular one is good at it, of course. But the role of management is often to manage external relations, with the non-technical world. They can either do that by having a few trusted technical direct reports who advise them, and they have the bureaucratic and political skills to manage relations with the outside world, or they can do it the other way. But virtually no one is good at both. The most important thing is if you are self-aware of which one you are not good at.