I think you raise a very interesting point.
How much "should" we "know" about "stuff" ?
A bit of understanding doesn't mean knowing the ins and outs, whys and wherefores of every single [thing]
But, that is the problem.
Because quite a lot of the time it is really helpful if not essential, to in fact, know a lot of the detail.
How else could you be sure you had reached accurate and comprehensive conclusions within the domain of interest if you did not ?
And what "stuff" is most important to know ?
Politics, economics, biology, chemistry, physics, brain surgery, physiotherapy, electrical engineering, psychology, advertising, criminal law, mathematical modelling, parenting ? etc etc etc
And how do you trade off time spent "knowing stuff" and "being productive" ?
Is British politics largely an exercise in massaging politician's egoes and the electorate's minds, and hence not really a "proper" subject ?
I think so. It's one of those subjects where any opinion is never definitively wrong or right and thus fair game for any punter.
And ironically even if you did "know", there's bog all you could do about it, or any methodology employable to demonstrate your accuracy.
"Knowledge" is curiously slippery.