I refer to this sort of thing as the Cosma Shalizi approach to objecting to something.
What you do is that you observe that you cannot point to an object in the physical world that has reified or exemplifies your chosen concept, and then proclaim it doesn’t exist and isn’t worth discussing. He used IQ, but many people (stupidly) use the tactic in many other areas.
I always ask them things like, “When you look at a single water molecule, where’s the wetness?” Or, “So tell me, where is love, or honor? You say you love your wife/husband. I don’t see any love anywhere. Point me to this ‘love.’ Therefore you do not and cannot love your wife.” That’s usually when the whining starts.
It’s shocking in ways that smart people can be so terribly stupid, but the STEM approach is that if you can’t measure something it does not exist. And to many in the field, “measuring” means with an actual ruler. Alas, that ethos has infected much of the rest of the world as well.
Now, to defend Shalizi a little, maybe he’s right about IQ. But his “proof” of his correctness was an atrocious bad faith hoodwinking.