And later, talking about the West: "As numerous studies of migration show, men - especially those in regions with declining economies - are initially more likely to move long distances for economic opportunity, while women are more likely to stay closer to home and family."
Admittedly these explanations don't make complete sense to me, though, and I'm suspicious of the phenomenon in general.
It didn't especially seem to line up with the usual red-blue lines, though the sudden shift in Florida seemed notable.
I am suspicious of it overall, but I'd need a lot closer look at the methodology to justify that.
East is old culture + institutions, west is new. Think new york + boston vs LA and SF. The east coast was settled long before cities on the west.
In broad strokes, men look to make something new / upend the existing order, and women fit into existing structures. Mirrors the age-old biological reality - men can concieve at any age, with multiple partners. Women have a limited reproductive window and carry the blood cost of reproduction. Women are more stable as caregivers, men are higher variance.
Not to say it all goes down like that, obv social norms change and people can be whatever they want, but the "bare metal" underlying biology has an impact.