I think the Sherriff's perceived "newcomer" status only surfaces after a situation like this. He was plainly considered to be resident enough to get elected. Having said this, I also have to point out, even in rural counties, what passes for an urban vote still elects officials.
In many places in rural Idaho, as in rural communities throughout the northwest, new residents are outnumbering those with lomgtime roots in the community. In many cases, these residents are in no way invested in the community as they are retired or are employed outside thecommunity. This can explain why there is such a disconnect between law enforcement and longtime residents. In addition, much of the contact rural people have with county officials is of an adversarial nature.
The so-called "rural" background of the deputies can also be a matter of perception. To a reporter from New York, someone who grew up in Moscow, Idaho might be considered to be of a "rural" background. To someone living outside Princeton, Idaho, not so much.
In the end it's all sociological BS but it does play a part. In Idaho, if your grandfather was born in California, that's a stain which will never be washed away (just kidding,sort of)! GD