If you want to work in a prison, you have to be able to beat prisoners with a baton. Hard.
Which is a nontechnical way of saying that if you can't lift a baton over your head with two hands -- as Bruce Furtado can't (as the result of an automobile accident) -- you cannot be a peace officer in a prison. The Court of Appeal holds that it's not an "accommodation" to excuse Mr. Furtado from this requirement, but rather would fundamentally change the nature of a peace officer.
You can see why. Sometimes inmates need to be beaten. And even if your usual job is filing papers, during a riot, we'll need all the beat-sticks we can muster.