Nobody says that _all_ people are unethical, or _all_ governments are corrupt, or that _all_ people in power are criminal. But rather, that being part of a government or having power does not prevent people from being unethical or corrupt. Bad people are generally a minority, but they do exist. That is one reason why we have government and police and military in the first place. But there is nothing that necessarily prevents bad people from becoming part of government, police, and military. That is why it is important to limit the power of those institutions. To limit the damage that bad people inside them can do. And also to limit the appeal to bad people wanting to become part of them. That's essentially the whole point of democracy and the separation of powers, BTW. It's a security mechanism that protects you from bad people in power - not because all people in power are bad, but because occasionally bad people manage to get into powerful positions, and that tends to end badly.