>These are all verifiable, measurable facts

No, they absolutely are not:

> whether crime is up or down

Depends on the definitions; what is or isn't a crime changes over time in a given society. Taking "crime" as an aggregate conflates many different possible crimes and relies on a subjective weighting of their relative severity. Crime rates can vary wildly between various subgroups of the population. We can only meaningfully compare rates of crimes that are actually detected and result in law enforcement actions; an unknown and broadly unknowable amount of crime is overlooked.

> whether the earth is warming or not

Most of the disagreement is about the rate of change, the predicted future rate of change, the predicted impacts of those change, the extent to which we can do anything about it, and especially about the relative importance of the predicted impact vis-a-vis the effort that might be required to do something about it.

> how many people live in poverty, what the rate of inflation is

"Poverty" is generally measured in terms of income versus an arbitrarily decided baseline. The baseline at best varies over time specifically to remain in "real" terms, i.e. adjusted for "inflation" which is calculated on a basis which may bear no relation whatsoever to the rate of change in costs practically faced by the poorer segment of the population. Furthermore, income is nowhere near the entire picture of wealth, which in turn is not a full picture of economic well-being. Inflation measures are designed with "hedonic quality adjustments" (https://www.bls.gov/cpi/quality-adjustment/questions-and-ans...) in mind which involve subjectively putting numbers on a wide variety of factors - they're literally trying to measure "how much better" a cell phone becomes if the screen resolution increases, so that they can decide whether the increase in price is justified; and in many cases they just resort to assuming that the initial price is fair relative to existing devices when the new one hits the market.

>How much social security or healthcare costs

Again, this has to be considered in the context of inflation adjustments, because the value of currency is not objective. World currencies are not a unit of measurement for value; it's just another thing that you can exchange for other valuable goods and services. If they were objective, there would be no reason for exchange rates to vary over time; they vary because, among other things, of varying relative faith in the issuing governments, and varying supply (which governments can generally control more or less at will).

Aside from which, there are valid reasons why the per-capita costs might vary due to demographic changes. The disagreements I've seen haven't been about the bottom-line number in (say) the American federal government budget; they're about how to contextualize that number. Are per-capita costs changing? Are your personal costs changing? Are the costs of people like you changing? (Those answers could be different for many reasons.) How do they compare to costs in other countries? Is that justified? Is it explained by extenuating circumstances? How shall we compare the corresponding quality of care?