Sir Richard, you are proceeding from the assumption that the political class acts in good faith ("these are people doing a job and trying to provide a service to you..."). I think this is why you cannot understand the anger and hatred of many of us who do not have such a rosy picture of our representatives. While doing a good and honest job is a consideration for all politicians who aren't psychopaths (and they're out there - trust me!), it is always weighed against other considerations (re-election, personal financial enrichment, desire for social prestige, hunger for power, getting sex from interns and lobbyists, free vacations, etc., etc., etc...) and almost always comes up short (although the exceptions - like the psychopaths - are out there).
Honest well-intentioned people generally do not last long in politics for many of the same reasons they lose in Diplomacy. Consequently, the end result is that all the people who are willing to sell out on good moral behavior and principles rise to the top the fastest - particularly in places like California where electoral districts are so large that the only way to win an election is to raise an obscene amount of money (which is always going to come primarily from people like government workers who expect their favor will be returned).
The anger and hatred is born when people look around and see how all the graft and corruption affects them and their standard of living. Nearly everyone nowadays has been negatively affected by government in some way, sometimes quite seriously. As government becomes larger, more powerful, more expensive, more intrusive, and kills more defenseless third-worlders every year, the number of people who have been seriously affected increases and they are almost always very angry; when they can trace their pain to a particular party or politician, that's when the anger becomes strong enough to be distressing to people who don't 'get it'.