They are pretty selectively chasing and interpreting his claims. I'm not a huge JD fan, but that's certainly not a fair treatment of some of his arguments. #4 is a good example of that; they don't even treat his actual claim or refute his statement, they just seem to say 'hey, other people did domesticate animals too,' which he clearly doesn't deny in his work.

Looking at it again, even #1 is weird. It's like they don't even acknowledge the silk road existed. We know contact and exchange was extensive between the middle east, east africa, and south asia through the Indian ocean circuits and the value of the overland routes that cross some of the territories mentioned in the list.

I'll just forgo ruminating on the rest; its pretty ridiculous. More so than even JD can be in the first place. They aren't quibbling over his ideas so much as they are trying to hack away at odd details.