Whenever people try to use the argument that something is right because it's 'natural', they pick and choose what they consider natural.
Human beings are violent at times. That's natural. They separate into groups. They demonize others or shun them. But they also co-operate and get along with others. They mix with other groups, exchange ideas and culture and form new groups. They procreate with each other too. Sorry white supremacists, but interracial procreation is natural. Multiculturalism is natural.
Any behaviour that happens is natural. Multiculturalism is happening and that makes it natural. But its not practiced by the majority of life on this planet and it hasn't been practiced for the majority of the time life has existed.
I doubt that it will help our odds for survival as our very low birthing rates indicate since we have adopted multiculturalism . The odds are those who practice multiculturalism will take themselves out of existence. Ending multiculturalism with them when they go extinct
A white supremacist this dose not make me.