Inferior cultures of less developed societies will always be "assimilated" into the superior ones if they come into sufficient interaction, this is how civilization is built, or else we would still be in the Stone Age. Diversity is just another means for opportunistic politicians, who have nothing else to offer, to buy the votes of the ignorant by feeding them the historic lie of equality. No political dogma, no genocide (Stalin, Mao and Pol Pot tried it) will ever make us equal because we are not, as not everyone is ready to achieve equality since equality is not given, is earned.