As usual, Claig, you're confused and incoherent and what you say is the opposite of the truth.
The majority of Parliamentarians are millionaires, and substantially richer than the public at large. Contrary to what the interviewee and yourself tried to imply, we don't have a Parliament full of highly-skilled entrepreneurs.
If you took ten minutes to Google the background of the members of the government - especially members of the cabinet - you'll find that actually they come from extremely privileged and wealthy backgrounds, and most of their wealth was inherited.
Most of the cabinet and prominent MPs come from Oxbridge backgrounds and were born in to wealthy families. Cameron is, in fact, a distant relative to the Royal Family. It's hard to image a more privileged position than that.
Not only have the majority of MPs come from privileged and wealthy backgrounds and inherited their wealth, but many of them are manifestly incompetent: Ian Duncan Smith is a perfect example of someone who is a complete loser at everything he does or did. If he were actually a manager or someone in a position of responsibility in a company he would have been fired a long time ago.
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Secondly, the argument is a lot more complicated than: "Being rich implies not knowing right from wrong." Firstly, it's a question of representation. The public have a right to expect their MPs to not be entirely unrepresentative of the population at large. The reason why this is important is two fold:
a) There can be a conflict of interest when someone who is rich and powerful and owns several houses, and is related to the Royal Family, and has strong connections with the City and the media representing someone in the public at large. It should be obvious that what is good for one group is not necessarily good for another group. Why should we trust MPs to make decisions against their own interest for the public at large?
b) No matter how well intentioned an MP may be, someone coming from such a privileged background as David Cameron will never, and can never understand and know what it is like to grow up poor on a council estate. They will never know the struggles that take place every day. They simply live entirely different lives. They can't even imagine what it is like, any more than someone who has been poor all their lives can imagine what it is like to live in security and privilege their whole lives.