You don't have to do the work through a capitalist middle-man employer, to answer your question, using your wording. You are talking about government taxes now, as opposed to capitalism. You were originally leveling your guns at capitalism. It is a switch. Thats the point.
Unscrupulous businessmen are a rare exception to the rule.
Most businesses are very honest. Your criticism isn't relevant to capitalism but to human beings. Ayn Rand explained on countless occasions to people like you, that criminals and thugs form a very small minority in human society. Capitalism is way down on the bottom of the list. It is not capitalism that is exploitative, but rather only certain capitalists.