You seem like a positively delightful person. Thanks for forcing me to watch my first Tucker Carlson segment since this keeps coming up [1].
I didn't hear this "direct quote" of yours anywhere. Tucker doesn't mention the "white race" at all, he speaks about government policies and how they influence native population growth (Americans born to Americans), and about the rate of immigration. If I missed your direct quote, then please provide a timestamp. While I find many of the supposed factual claims there debatable, this argument that too much immigration can be destabilizing is not obviously false.
What I've seen time and time again in situation like this, from both sides, are claims of "dog-whistling", wink-wink-nudge-nudge "we know what you're really talking about [insert-person-I-hate]".
I'll also note that "demography is destiny" has been an unofficial Democratic party tag line for decades now. The notion that Democrats have more vested interest in increasing immigration is not exactly a conspiracy theory, although given how the Latin population is now leaning Republican I think they're realizing that that tagline is deeply flawed as an actual strategy.
Tucker Carlson thinks that immigration is ending the white race. That's a direct quote, go watch the segment.