I'm reposting the below, with edits, here in an attempt to address "It's always an us versus them mentality." as you said in your post.
My Dad was a New Orleans Police Department Cop for 25 years. 19 of that as a solo Traffic/Foot patrol officer (1955 - 1974). This on the Canal St edge of the French Quarter, with Greek Sailor (and many other crazy, balkanized) bars, and an incredible mix of tourists, street people, grifters, addicts, criminals and businesses.
When sailors walked off their ships along the Mississippi River, from around the World, they walked up Canal St directly onto my Dad's patrol beat. (From the river, you had to walk past him to get to Bourbon Street, a few blocks up Canal St.)
In 25 years of active police service, my Father never had to draw his weapon in the line of duty (except on the range, and he didn't much care for that). He carried a night stick made from an oak table leg with an iron pomel, and he did thump heads (with his fists) when he had to. (I once watched him break up a bar fight by drinking a beer at the bar, and pulling another tired body off of the dog pile, between sips of beer, until he got to the instigators at the bottom.)
He was doing interactive/proactive "community policing" (on his feet 8 hours a day - not sitting in a car) long before the term existed, or became a catch phrase.
Then in the mid-70's New Orleans followed LAPD's lead, and phased out foot Beat Patrol Cops and put everyone in patrol cars. This isolated LE from the people they were sworn "to protect and to serve". That is when everything started to go downhill, and the "us versus them" mentality started to grow and fester, and this change is what has brought us to where we are today.
American LEOs are now drilled and trained to respond exactly as AG did. It started in Los Angeles after two cops were executed with their own guns in an onion field in 1963 ("The Onion Field" by Joseph Wambaugh). After that, LAPD changed their training and tactics, and the rest of America followed suite. (Remember the Adam-12 and S.W.A.T TV shows? Thank Jack Webb, a LAPD fan). Leading to patrol car officers only and the militarization of U.S. LE Departments.
SWAT, foot beat cops replaced by patrol cars, the "21 foot rule" ( THAT Cop's death happened in a Colorado bar), 2 rounds to the center of mass and repeat until the PERCEIVED threat is neutralized; these are LAPD innovations that lead us to a "us versus them" policing policy, that in turn lead to the Rodney King incident, and all that has followed since.
This culture made AG what she is, for this reason, the "thin Blue Line" will protect their own, but only up to a certain point.
Like Jessica Rabbit, Cops aren't bad, it just has to do with how they are trained to do their job, in a VERY hostile environment.
"Those who do not remember their history, are doomed to repeat it"
Please look at how we got here, in order to begin to find a way to fix the problem.
By the time my Father retired in 1980, he was not comfortable with the new breed of Cops on the street. The horrific wave of police violence, corruption, and police drug trafficing in New Orleans, that followed his retirement, tells me that Dad still had good street instincts, and that he was right. It was a good time to get out of Dodge!