Me, too. I was taught “police [man, woman or officer],” but “cop” only used privately, among friends or when you *mean *to be insulting. I am still shocked when I hear news anchors use “cop.” But then, I am very, very old.
I can honestly say I’ve never heard anyone say cop in a way that I took to be offensive. This thread is the first time I’ve heard of it being pejorative.
It’s certainly informal and it would strike me as odd, and perhaps a little rude, to address a police officer as a cop to their face (unless you knew them or were in an informal setting). However, the term itself isn’t derogatory. It’s not the difference between “ma’am” and “WHORE!” So much as the difference between “Hello, how are you?” and “'Sup, brah?”
ETA: It seems to me that to give a rather sitcomish example, if you met your girlfriend’s (police officer) dad for the first time you’d rather say, “So you’re a policeman, right?” Whereas if you were more of a laid-back, informal Shaggy-from-Scooby-Doo type person you’d say “So you’re a cop, huh?”
I volunteered as an auxiliary cop in the early 70s. “Cop” wasn’t offensive, but wasn’t all that commonly used, as I recall. The police chief always wore a pig tietac. His position was that PIG stood for “pride, integrity, guts”. Not a good idea to call one a pig, though. I saw it happen once. The 350 pound officer I was riding with had the guy pretty shaken by the time the encounter was over, and he never touched him.
When I called a Mass. state trooper “officer”, he gently corrected me to “Trooper”. I should say that I am 74 and he was changing my tire because AAA could not find the highway (Route 122) on their so-called maps. So I was being especially respectful. Trooper Driskell, I will not forget you. He said that his parents were my age and he hoped that if something like happened to them, he hoped someone would help out.
My neighbors on both sides are cops, one is a married pair. Michael, the one I interact with most, always calls himself and his fellow LEOs “officers”. For example “Another officer and I chased the suspect down in the VA hospital parking lot, where he rammed my car as I was exiting and tried to run the other officer down.” (True story of his).
Funny story - I got my dogs a squeaky pig dog toy. It was Andy’s (the german shepherd) favorite toy, he carried it everywhere. One day Michael called me to ask if my dogs had a pig toy - Andy had left it at the entrance to their driveway, facing out, perfectly straight. He thought maybe someone left it as some sort of social commentary.
StG
I’ve noticed that RCMP officers here in Canada tend to refer to each other as “members”, i.e. members of the RCMP.
My father, who had relatives who were police officers, taught us that cop was not nice to say, but that was in the fifties. I think he felt that one officer could call another one a cop, but it wasn’t for outsiders. I don’t know how police officers feel about it, but I think most people now think that saying cop is not a problem.
I’ve heard of private dicks, but that’s new to me.
Criminal #1: It’s the cops!
Criminal #2: Worse. The Police Cops!
I saw an episode of Law and Order where Dennis Farina’s character said cop was disrepectful and made a detainee say officer.
My father was a police officer for 43 years.
He didn’t mind “Cop”. He said it often and even now where I am going to school for criminal justice. “Hey BB, You going to become a cop!?”
Never say pig or bacon around him. He will come unhinged. Depending on the day, donut jokes piss him off too.
But I remind him often that while he doing the night shift, he would always bring home fresh donuts. First guy in line was the cop. He opened himself up to the jokes. haha!
True Story. Woman at work buys a used police car about a year or so ago from local dealer who handled the sale. A few weeks after having the car, she finds, under the seat, a mummified jelly doughnut. I know-anecdote.
That’s okay. More yummy bacon and doughnuts for me!
What would “pigs-in-blankets (UK version of ‘pig-in-a-blanket’: bacon wrapped sausages)” be considered?
Double negatives hence positive or twice as much “unhinged”?
Speaking of pigs, I’m reminded of a photo, in the Bangkok paper but of a protest in Europe I think it was. I can’t remember what the protest was about or why at least one protester was dressed like a pig, but he was being arrested. The photo caption said, “A police officer (left) arrests a protester…” I assume just so you’d know which pig was which. 
NOTE: I like cops myself.
I have encountered the use of “cop” so commonly both by cops and non-cops that I wouldn’t be surprised if sometime in the near future, it’s used in an official name – “Municipal Department of Cops” – “Cop Sgt. T. J. Hooker.”
I think part of the reason it switched towards neutral is that it was a gender neutral term in the language as our language switched more towards gender neutrality. “Who’s at the door?” “It’s a police.” “It’s a Policeperson.” “It’s a cop.”
I like good cops and hate asshole cops; Ratio of ‘good, bad, and ugly’ is pretty much the same everywhere.
In one of my careers I’ve dealt with law enforcement management a lot. “Cop” was pretty much the universal term they used for each other.
When I was a kid back in the 60s, “cop” was certainly informal and mildly disrespectful. I still see it that way; Ok for them, not really OK for us except in the third person.
Q: what do you call a police car with 2 officers?
A: A double rasher.
Not a joke I tell around police chiefs.