Also, intelligence tests are but a tiny part of psychology, I would hardly call it a "whole field".
Sure, and NQ tests do too, because look how well graciousness correlates with cheerfulness! That can't be an accident, can it?
Less snarkily, a better analogy would be athletic ability. Suppose you take a bunch of people and measure how fast they can run, how well they can shoot free throws, and how far they can throw a football. Will the results be correlated? Of course, some people are more athletic than others. Does that mean there's a quantity called 'athleticism' that we can objectively measure with a number? No; and not because all people are equally athletic, but because you're trying to take a squishy subjective English language word and pretend it's a scalar value.
> I would hardly call it a "whole field".
The problem isn't the size of the field, it's that academics work within their field, they don't refute it. There's a very uncomfortable result about IQ tests that a generation of psychologists have tried to explain away, and I maintain that the reason they haven't succeeded is because they are institutionally incapable of saying, "Hey, maybe this is pseudoscience."
As noted in the study, the largest influence they tested for archery performance was height. I'd bet a large sum of money that height is also a strong positive influence on many sports (eg basketball), similar to how G is an influence on many cognitive 'sports' like occupations. We can easily measure height and most would have no trouble believing that (largely genetic) factor greatly influences athletic performance. Why is IQ so different?