Maximizing GDP doesn’t need to be the primary goal to as you say guide policies. There are plenty of policies aimed to increase economic growth as measured by GDP.

Economists however are on all sides of this issue, it isn’t some monolithic field where everyone agrees on even basic ideas.

What economists are on the side that GDP is a perfect measure that precisely captures the increase in well-being? I have never heard of one. If you look at the IMF website you will find a nuanced explanation of what GDP is and is not. For example, it states that

> It is also important to understand what GDP cannot tell us. GDP is not a measure of the overall standard of living or well-being of a country. Although changes in the output of goods and services per person (GDP per capita) are often used as a measure of whether the average citizen in a country is better or worse off, it does not capture things that may be deemed important to general well-being.

Tirades that when economists calculate GDP the human society is serving "abstractions" or the devil over the "real" and God is just fearmongering.

Again your taking things to unreasonable extremes, plenty of economists think GDP is good enough to be useful. Which means it’s informing their decisions or it wouldn’t be useful.

You can’t say measure X is useful, and it’s flaws are well known therefore it’s flaws are irrelevant. If it’s useful then it’s flaws are part of any decision made using it.

>plenty of economists think GDP is good enough to be useful. Which means it’s informing their decisions or it wouldn’t be useful

Yeah, that's precisely my point. It's informing their decisions.

>You can’t say measure X is useful, and it’s flaws are well known therefore it’s flaws are irrelevant. If it’s useful then it’s flaws are part of any decision made using it.

Measure X is useful, its flaws are well known therefore people who use it account for its flaws during the decision making process.