Could be something to do with chances for mating, Asian women got much higher chance to find a western husband compared to Asian guys finding a western female t

Could be something to do with chances for mating, Asian women got much higher chance to find a western husband compared to Asian guys finding a western female to marry them. In south east Asia people immigrate because of financial struggle so they don't care about this too much but in first world Japan and Korea, where people immigrate because of other reasons, it might be a factor.