I’m pretty sure the parent is pointing out that the chemical combustion in eg a caveman’s campfire required many millions of years of stars performing nuclear fusion to create any elements with higher atomic numbers than 2, oxygen included.
I agree. I am talking about technology as of what humans control. Humans do not control this -> "many millions of years of stars performing nuclear fusion to create any elements with higher atomic numbers than 2"
Oh, I read it as a reference to natural fission reactors, like the one found at Oklo.