It is the notion … " the “white race” is being squeezed out of existence through its own low birth rate, miscegenation and more prolific reproduction by non-white people." (From The Economist.)
Fair enough, but not enough. The question is if (a) there is a basis to it and if so, (b) is it bad? The statistics of the last hundred years surely confirm the trend. Humanity is brown and the "white" (I prefer the classic Chinese description of 'colored people' or the people with colored eyes and hair) are getting scarcer. I love multi-colored girls (Sadly, only in past tense) and not attracted to big butted African girls, so - for me - it is a (notional) loss.
Is the fear of replacement bad? Taken to the extreme of racism, it is. The Nazi Party, professing its iron will to save the colored eyes people, attacked its neighbors - who were more "white", "pure" and colored than they were, the Polish and Ukrainian peoples. (And Ashkenazi Jews, who are lighter-colored than most Germans, you didn't know that.) Ten million Germans died. How you save your race exterminating your own race? The Nazis said one thing and did exactly the opposite. Ergo, racism is bad, causes people to harm themselves.
More than, I don't know. The girl in the pic resembles my cousin in Australia.