I find this line of argument very unconvincing. Would you apply it to the question of whether inflation and/or unemployment went down during Regan's term? Do you really think this has anything to do with the precise definition of those quantities?
Inflation is only hard to define for those who want there to be something called "inflation" that predicts recessions and is caused by the government. Naturally it's hard to find anything to nail down within those parameters.
In the rest of the world inflation equals price increases and there are standard metrics that have been used for decades. Most economists would probably agree that those metrics have several well-known flaws. But we can agree that inflation according to the definitions and metrics that 99% of the world uses did or did not change by X or Y in a given time period.
The fact that the existing metrics are flawed mean that it's perfectly reasonable for a person to both:
(a) Believe one thing
(b) Understand that the "accepted fact" contradicts their belief
If no money is on the line, this reasonable person will state their belief. If money is on the line, they are more likely to state whatever they think the "accepted fact" is, regardless of their true belief.
In politics, there are many things for which minor differences in interpretation can cause a "fact" to change between true, false, and unknown. Inflation is certainly one of those things.
Thus far, I'm agreeing with you. Facts have nothing to do with the rhetoric being spewed. It's all just tribalism.
As a progressive, I had believed that we could all reach some kind of agreement, if only we could talk it out. Not understanding why that wasn't working, I started researching (Don't Think of an Elephant, What's Wrong with Kansas, etc) and experimenting (practicing talking points on right wing family and friends).
It's been illuminating.
One of my brothers was advocating higher effective tax rates, deficit reduction, and so forth. So I said "So you'd support returning to Clinton era policies?"
The answer surprised me.
He said no. I asked why not. After some musing, he told me Clinton era economic growth was a "false economy". Um, okay. If he had something about bubbles, I'd totally agree. But all he had was "false economy". Probably something he heard on the radio.
I've had similar discussions about healthcare. Every single value, position, complaint, etc would suggest the belligerent would support universal coverage with a single payer. But dare suggest it and there's a strong reaction. Hell no, that's socialism. Or whatever.
I've decided there's no profit in attempting persuasion.
The only successful strategy is to organize better than your opponents. The purpose of rhetoric (messaging, persuasion) is to motivate one's supporters or neutralize opposition.
The question "did X go up during Reagan's term?" is probably correctly answered "yes," at the same time "did X go down during Reagan's term" is correctly answered "yes." Because some things move both up and down, and the question isn't explicit that it is asking about the overall trend.
