Re: Why not just...
I think a lot of politicians maintain an intentional ignorance of the topics upon which they opine, on the basis that they cannot be accused of lying if what they say is either (a) not known by them to be untrue* or (b) not believed by them to be untrue. Credible bullshitting relies on you not knowing what you are talking about, because psychologically, you are not working against the feeling that you know what you are saying to be an untruth. Others achieve the same effect by simply not caring if they are lying - such individuals are can be dangerous.
This also goes some way to explain why many** senior managers are uninterested in the details. Ignorance can be very powerful.
*The partially successful Amber Rudd defence.
**Not all. I have been privileged to met some of the few exceptions.