Sounds like you've had unusual experiences with the courts. I can't force you to base your opinion off of more typical experiences, in large part because you haven't lived other people's lives (or looked into their court cases).
Back to my metaphor, if a seat-belt trapped me in my car, I wouldn't decide that must be normal and I should never wear a seat-belt again.
A radar detector is very different from a dash cam, including in law depending on your area.
I think you're just doing mental gymnastics to make a reason for not getting one. Just be honest with yourself and say "I don't feel like it."
It reminds me of the people who point out that seat-belts trap people in cars so they won't wear a seat-belt. They don't think rationally about the very remote odds of that, they just latch on to it as an excuse to do what they were already going to do.
There are tons of nightmare scenarios you can avoid by having a dashcam including the police lying about something you did while driving, which could lead to all sorts of awful things for you.
The thing is, smarter people think better than to speed while carrying a body or a kilo of cocaine in the trunk, but smarter people tend not to commit crime as often, on average.
So as much as it makes no sense to you, it does when you factor in common criminals. Supervisors monitoring your KPIs don't care if the arrest was made on a dumb person or a smart person.
If it were me, I'd respond: "Okay, I'll follow you to the nearest public bathroom, but you're still getting the citation."
Someone pulled that on me once, but I saw them pass a few public bathrooms as they cut around a line of cars in traffic to get to the turn lane a bit faster by going down the wrong way of the roadway, so they were obviously lying.
You might have more luck with your lie among lazier/less discerning/dumber cops, it's true.
In my area (HCSO, PCPD) you could tell by their boots: jackboots = traffic enforcement.
Of course there's also FHP, who are basically an entire agency of only traffic enforcement.
I'd recommend getting a dash cam and your speedometer calibrated, just in case you got a wheel resize or gear configuration change that made your speedometer inaccurate. We were required to calibrate our patrol cars every year if we used it to measure speed, but there is zero such requirement for random motorists. I think the LIDAR and RADAR guns were yearly too, but I never applied for the class required to use one so I'm not sure.
You're basically talking about the difference between traffic cops and regular patrol.
More pedantically, it's "Traffic enforcement unit cops" or "Cops who went out of their way to take a speed measurement certification course and get issued the equipment and thus are expected to use them or lose them" vs. "Cops who didn't."
As you can imagine, the latter doesn't care nearly as much about traffic enforcement.
I'm not saying you don't have cause to be a bit silly about this, I'm just trying to get you to realize you're being a bit silly about this.