Well, where should I start? A few examples:

• The Roman Empire reached its maximum extent under Trajan circa 100AD. (And even that was a fairly small increase relative to a century earlier under Augustus.) Signs of crisis started appearing only towards the end of the 2nd century, and Christianity started being officially tolerated only in the early 4th century. How these centuries of non-expansion before Christianity entered the political stage can be reconciled with the theory from the article is beyond me.

• There is clear evidence that the fall of the Roman empire occasioned a huge fall in living standards throughout the former Empire, including its provinces that it supposedly only pillaged and exploited. (See The Fall of Rome and the End of Civilization by Bryan Ward-Perkins for a good recent overview.)

• Ascribing the decline in masculinity to some mysterious "reprogramming" that is narrated in passive voice strikes as me as bizarrely incoherent.

• Large cities are not a modern invention. In the largest cities of the ancient world, enormous numbers of men (certainly on the order of hundreds of thousands) lived packed together much more tightly than in modern cities. How did the states ruling these cities handle that situation, if the mysterious "reprogramming" occurred only in the last few centuries?

• In the antebellum U.S., the South was not fighting to implement federal tariffs, but opposing them bitterly.

• Cotton picking wasn't widely automated until the mid-20th century. How long slavery would have remained profitable without abolition is a difficult question, but in 1861, "mechanical reapers.. mak[ing] slavery uneconomical" were still firmly in the realm of science fiction.

• If the reason for the lack of interest in slaves in the North was their short growing season, then the ongoing industrialization should have changed that. Factories can utilize labor profitably 365 days a year. So clearly other factors were more important.