Racism is not bound by facts - see our current administration.

We're debating "replacement rates" and immigration because it turns out only people who are currently in power benefit from a party that maintains the status quo. This leads to that party gripping the status quo reigns ever tighter, and in turn to most non-majority people voting against them. Well, turns out a lot of the minority are immigrants, so the status quo faction now yammers about "replacement rates" and wants to keep immigrants out - because they're aware they can't hold onto power under a democratic system that allows immigration.

And so, racism and fascism takes hold, and facts are jettisoned for the benefit of holding on to power.