Why do right-wing authoritarian regimes allow so much citizen exit?

Derek Bonett emails me:

I’ve been considering the differences between left-wing authoritarian regimes and right-wing authoritarian regimes throughout history. One particular difference springs to mind that I do not believe has been explored:

Left-wing authoritarian regimes very frequently restrict emigration. Legal emigration from the U.S.S.R. and the Eastern Bloc was very difficult, same with Mao’s China, Castro’s Cuba, the DPRK, “Democratic Kampuchea”, Ethiopia under Mengistu, the list goes on.

But, strikingly, it seems to me that with the partial exception of the Third Reich, fascist/ultranationalist/right-wing authoritarian regimes generally do not restrict emigration. In the Third Reich, it seems that even Jews were allowed to emigrate until 1941. Mussolini’s Italy didn’t impose extensive emigration controls either. And, accordingly to my admittedly casual familiarity with these regimes, neither did Franco’s Spain, Salazar’s Portugal, Pinochet’s Chile, nor the more generic authoritarian regimes of Chiang Kai Shek’s Taiwan or Park Chung He’s South Korea.

Does your much more comprehensive reading of history confirm this difference? Has someone already written about this?

Perhaps the more “right-wing” regimes tolerate different sorts of income inequality.  Cuba and the USSR had plenty of inequality, but the main earners, in terms of living standards, are restricted to people within the state apparatus.  That means a lot of the talent will want to leave.  Many fascist regimes, however, are quite willing to cultivate multi-millionaires and then try to co-opt them into supporting the state.  Since you can still earn a lot in the private sector, exit restrictions are less needed.

What would be other hypotheses?