Yes and no... Historically, the Sheriff is the "top cop" in the county and can be arrested by the coroner. In practice, any officer can be arrested by any officer.... BUT
the difficulty comes when seniority raises it's head. ie. "if" patrolman joe doaks is drunk and unruly, the proper action would be to have the supervisor on scene. "If" he is the supervisor, have the chief or sheriff as the case may be. This would be whether on or off duty. Even though there is the blue line, the majority of agencies will handle the case as it should be done. It may and probably will take longer and be of a lower profile in order to protect the department image. As we all know, one bad apple makes a barrel full. Not only in OC but in everything we or they do.
I know there will be some that think this is a cover up and I am certain that there are times that it does happen. Those times do finally come up and it gets real nasty real quick.
Don't use that wide brush to paint every incident, OC or LEO. Give things chance to be handled appropriately.
Flame away with your negatives, but life is not pretty.