Let's breathe some fresh air, and common sense, into these numbers.
Generally, when talking about getting one's rights or person violated by cops, one is talking about a regular patrol officer. Could include a sergeant or lieutenant; I've had lieutenants respond to calls when they were really busy. But generally, we're talking about patrolmen, not supervisors, and not command staff, either. You know how many superfluous, redundant layers of command staff a department like New York or L.A. has? I read about NY's hierarchy and was amazed: Superintendants, Deputy Supts., First Dep. Supts., chiefs, Super Chiefs, layer on layer. You're essentially never going to encounter them in a situation.
We're also not counting detectives. Detectives can screw you by how they treat evidence, a la Mark Furman, and sure, they could theoretically use excessive force, though your chance of a detective using any force on you at all is essentially nil. The average citizen will never have any such dealings with one, unless he's a habitual criminal, and that brings its own problems.
So what cop might victimize you today, realistically?
Obviously not those on their days off, out sick or injured, on vacation, on some special duty that takes them away from patrol, the cop that runs the evidence room (if a cop does it at a given department), not evidence or other techs (if cops do that there), or any other cop on desk duty. At places I've lived, there were sworn law enforcement personnel working posts that didn't resemble law enforcement, such as manning the Emergency Management position or working corrections. A friend of mine worked what was called the Pawn Unit, who were responsible for tracking down stolen/fenced property through pawn shops; she was a sworn officer in that 860,000+. The department had a telephone reporting unit a citizen could call to report a crime so a street officer wouldn't have to stop patrol to take a routine report; they were sworn officers. Maybe those were cops on temporary light duty, I don't know. But they were all cops you'd never encounter on the street and wouldn't have an opportunity to abuse you if they wanted.
In fact, I read that NYPD has guys on static posts all over--hundreds of them--essentially doing guard duty. Not guys picking up a few bucks after hours, guys whose police duties were to guard a specific place. The example given was a cop stationed at a synagogue that had had vandalism problems. They were posted there, probably supposed to be temporary but were just forgotten, and now that's turned into their permanent post. Nobody ever thought it necessary to reassign him, so there he reports, 5 days a week, not doing much of anything except huddling in a doorway, guarding a building, yet he's sworn law enforcement personnel. That might have changed when Guiliani restructured to get more cops on the street, but the book said that had been going on for years & years.
So how much does cutting it down to the regular cops you're going to encounter affect the numbers? I couldn't say, and I don't know how to figure it. But when you do that, the relevant number is substantially lower than 860,000.