I'm not saying that it is inherently evil, I'm saying that you as a member of the public must assume that it at least has that potential at all times for it to function as intended.
And the grand-(N)-parent 'bkor already answered this by saying that it becomes a self-fulfilling prophecy. Yes, the government has potential for doing enormous evils, which comes from its very nature - it's large and has monopoly on violence. But people having a cooperative, instead of antagonistic approach to government helps that potential to go unfulfilled.