It's not reverse sexism; Remember, in old times, raiders or the victorious army would take the women and kill/enslave the enemy males so that they would be victorious. It is considered a victory for Asians if we let in a large majority of white females only, while we keep the men out. They will assimilate, and we will win.

I think there can be negative sides to hapas, whether its a white father OR a white mother. In small numbers, it's true hapas can mostly assimilate in an asian oriented country (especially if its half white half asian as its hard to tell), but in larger numbers I think it's best to keep the bloodline of a country pure.