All Peer Reviewers are Equal, But Some Peer Reviewers are More Equal Than Others

The peer-review of scientific papers is in one sense democratic and in another sense highly authoritarian and dictatorial. What is most important is that the scientific peers with the most appropriate level of expertise review a given manuscript which is seemingly democratic. What is most critical, after all, is that the science itself be reviewed with the greatest scrutiny and held to the highest standard, right? The identity, status and formal credentials of the reviewers are less important than is the specific type of expertise.
So what is up with Editorial Boards?