I understand the phenomena the article is talking about – being authoritarian about some things while hands-off about other (possibly much more major) things –

I understand the phenomena the article is talking about – being authoritarian about some things while hands-off about other (possibly much more major) things – but I'm sceptical that the proposed historical explanation is correct. Here's my own take: the recent history of the West in general, and the US more particularly, has been a conflict between two competing worldviews – one relatively "traditional", the other calling itself "progressive". And go back to the 1960s, the competition between the two worldviews seemed relatively coherent – the "traditionalists" controlled most of the power structures in society, the "progressives" were (by and large) an anti-authoritarian rebellion against those structures. But, 50-60 years later, now the "progressives" (and their heirs) have come to dominate large sections of those same power structures, and they've swapped their prior (relatively consistent) anti-authoritarianism for an inconsistent mixture of authoritarianism about some things and anti-authoritarianism about others. You can see the same thing in other Western countries – even if not to quite the same degree – who have rather different ethnic histories. That's part of why I'm sceptical that appeals to the history of different Anglo subethnicities really works as an explanation.