> it's always seemed really odd that some countries (Japan sticks out) are allowed to prioritize cultural preservation

can we clarify... by whom? just kidding :) whether a country is "allowed" to do something is probably a red herring.

spitballing here, i think folks who engage in criticism of ethnonationalism are most likely to criticize the ethnonationalism they see close to home, as opposed to what might be happening on the other side of the planet.

there are valid critiques of japan's treatment of its nondominant ethnicities, and lots of anecdotal experiences covering the same, but it's a lot easier to discuss the nuances of an issue like this when you're more intimately familiar with the culture and sociopolitical history of a region.