for humanity to survive for the next few hundred years, a precipitous drop in population to more sustainable levels would be wise.
If the adjustments are "simple" fixes like curing a disease by correcting a mutation or two, I see no problem with it.
But if it's about making a "super race" by fiddling with body type or the brain, then I say let other countries be the guinea pigs and learn the hard road lessons of fiddling.
You are implying some arbitrary normal human as a baseline reference. And the only difference between those two scenarios is whether you are moving someone up to that baseline or past that baseline. But why should we set the goalpost at average human instead of setting the goalpost of optimum human potential? Most of us who aren't Olympic-level athletes and super-geniuses all has some genetic conditions that hold us back from reaching the greatest heights of human achievement. If those conditions can be fixed genetically, then why shouldn't they be? That's like saying that only people who are bad at math should be allowed to use calculators.
He keeps differentiating, flying off on a tangent.