Interestingly, Bird never actrually justifies his 100% environment hypothesis with a positive argument but claims it would be easy to do with his assumptions about economic exploitation and colonialism (which is dubious since SES does little to ameliorate the gaps we see). Instead he does what they usually do: argue you cant even inquire into this matter. Like arguing that continental categories are useless because it could be more precise, or that GxE complicates heritability (and somehow I doubt it justifies 100% environment), or demanding a specific selective pressure be identified.

All of this is true, except the last one, to some extent. But it's hardly a case for 100% environment. Just makes determining the exact genetic contribution tricky.

His argument about borders was dumb. You can call borders authoritarian but somehow forming a coalition with those immigrants for your preferred policies (since Bird is a lefty) to disenfranchise the effect native voters have isnt authoritarian at all? Pathetic. And yea, open borders isnt identical to not being isolationist. Hell, East Asian nations are pretty close to isolationist in terms of border policy but arent inbred. Not even North Korea is.
And we cant have white immigrants? It makes sense to take people from developed nations rather than undeveloped nations anyway.
And the idea that cultural exchange is equivalent to open borders or whatever was dumb
Kinda goes along with his general idea that because we cant keep things static we should consent to all changes. I guess because no group is identical to 100 years ago we should not care about what we can help at all?