If you think about it, it's actually not weird at all. Look at the rich libs in western countries that completely ignore all of the bullshit the general public puts up with on a daily basis because they live in a gated community or apartment with a doorman/security type shit. They're not commuting on a shitty NYC subway for a daily job or driving for hours on freeways elsewhere for hours to get to and from work. They're already insulated from grocery cost increases by having the money they do on top of that. But this shit is obvious.
Now factor in being rich and moving to a place like Japan, or getting rich while being there. Now you've got someone who may have been slightly left leaning in the first place, in an area about the size of California, with none of the bullshit that California has. Japan doesn't have heroin needle filled parks like San Francisco, or illegal alien filled ghettos like LA. The place is practically a utopia by comparison making it even easier to go about your life without any consideration for the average person in a western country and the bullshit they have to put up with daily. Does that mean they'll actually consider why Japan is basically a utopia compared to places like California or NYC? No. And if they get the ability to vote there, they'll just vote for the same shit that fucked things up elsewhere like when people flooded from NY and CA to parts of Texas and then started fucking that up.