Zarek's rhetoric was geared towards making the current administration look as bad as possible. He's a smart guy - I'd bet that he realizes the flaws in his argument, himself, but he's not exactly going to point those out to the people he's trying to turn against Roslin. ;-) It's all about gaining power for him; he's deliberately playing on the old, planet-based, anti-current government ideology because that's where most people still are (only mentally, obviously).