You got the wrong Arthur Dent quote - should have been this:
“It comes from a very ancient democracy, you see..."
"You mean, it comes from a world of lizards?"
"No," said Ford, who by this time was a little more rational and coherent than he had been, having finally had the coffee forced down him, "nothing so simple. Nothing anything like so straightforward. On its world, the people are people. The leaders are lizards. The people hate the lizards and the lizards rule the people."
"Odd," said Arthur, "I thought you said it was a democracy."
"I did," said Ford. "It is."
"So," said Arthur, hoping he wasn't sounding ridiculously obtuse, "why don't people get rid of the lizards?"
"It honestly doesn't occur to them," said Ford. "They've all got the vote, so they all pretty much assume that the government they've voted in more or less approximates to the government they want."