"Its like how they make cop shows and movies where the criminals are all Machivellian geniuses to make police seem more competent. "
Many shows and movies are specifically about catching the criminal geniuses that regular cops can't.
And very often (EG CSI, Bones) the criminal is pretty normal, it's just hard to figure out what happened.
House MD doesn't make medicine complicated to make doctors look better. If it's a cop like Harry Bosch, cold cases are complicated by time. Bosch doesn't (just) succeed because he's smart, he succeeds because he's persistent, and often breaks Da Rulez.
Which has gotten himself and others hurt and killed.
Also, who wants to see "oh, the husband was found with the murder weapon in his hand, standing over the body, and he was caught in 4K stabbing his wife. Case closed. "?
What will you fill the other 39 minutes with?
Writers have to complicate the plots to make them entertaining.
There's also plenty of complex mysteries where the investigator is not a cop, or even a private detective, technically. And the real cops will go "drop the case". Several times.
Fincher's "Zodiac" focuses on journalists, and some of their lives get wrecked by the case.
Robert Graysmith lost his wife and the kids. And wasn't even a reporter! He was a cartoonist!
And there are several famous mystery works where the answer turned out to be SIMPLER than the investigators thought.
Very often in mysteries, there's a moment where the investigators realize there was something simple they overlooked the whole time. Maybe they rush to stop the bad guy and barely make it in time.
They can't make the cops hyper-competent without losing drama. Which is always ignored.
Bottom line: This is a stupid claim made up by the sort of people who call everything with cops "copaganda".
Yeah, even if most criminals are stupid, stories about catching stupid criminals are boring. The only way to make it interesting is the way Colombo did it. (Note: I'm not saying the criminals Colombo caught were stupid...though they did have a real tendency to overthink their schemes. They were clever.) Colombo pretty much *immediately* zeroes in on the guilty party (just as would happen with a stupid criminal), but the show is all about how he dances around the bad guy, often for days, slowly and methodically picking apart his oh-so-clever ruse to avoid being found out, until he finally demonstrates that he knows exactly how it was done, and can prove it, and arrests the guy.
Also, real world cops with even just a few years on the job, will have VASTLY more experience dealing with suspects, ferreting out lies, and manipulating the suspect into incriminating himself, than most suspects will ever have trying to talk their way out of trouble. The cops do this EVERY DAY. The suspects, frequently, have little or no experience trying to lie to the cops. Or they do have it, because they're long-time criminals, and the cops are probably aware of that fact, and so even more suspicious of their lies even if they're practiced liars.
So we get stories about clever criminals because they're more interesting. Generally. I personally am sick to death of the genius serial killer trope, who is always three steps ahead of the cops until the last minute.
I was on a grand jury once, and the FA came in to speak to us a few times. One of the things he said was that TV and movies make it seem like murders and kidnappings and rapes are these huge mysteries, but in real life, the actual murderer/kidnapper/rapist is, more often than not, exactly the person most likely to have done it. More often than not, the actual culprit makes so many stupid mistakes that there's abundant evidence and plentiful holes in their story.
I've been on grand juries twice. Once in Virginia for a day (technically, two weeks, but it was a small rural county) and for two weeks in Portland, OR a few years ago. We saw everything from passing bad checks to murder cases, with LOTS of auto thefts in Portland (apparently druggies will break into cars for a private place to shoot up and sleep off the high, trash the car in the process, and then abandon it--they don't drive it anywhere, but it's still auto theft). And, as a grand jury, we only ever hear the prosecution's case, since we're there to determine whether there's enough evidence to go to trial. I think we only rejected a few charges the whole two weeks (and even then only one or two of several charges for an individual, so they were still going to trial on others).
I've also served on a criminal trial. The accused broke into a house in search of drugs. After shooting out the sliding glass door onto the backyard balcony. They a) apparently had the wrong house, and b) claimed they fired in self-defense, but I believe that one of them had an accidental discharge of the gun he was carrying, and they saw the muzzle flash REFLECTED IN THE GLASS DOOR (it was dark at the time), which shattered, and they panicked. One of the idiots obviously made a deal to inform on his buddies, but when he was on the stand, he hemmed and hawed and completely failed to provide any useful testimony. Finally the DA ended the questioning, saying to him, "And I'll be talking to YOU later." I suspect he lost his deal.
