And in 2016 they elected Trump.
FACT.
If the USA continues to import every poor person on the planet, the liberal social welfare programs you love so much will eventually disappear. So it's actually in the best long-term interest of your ideology to not strain the system too much with people who overly depend on it.
That's why White people, who disproportionately pay into social services on a per-capita basis and don't consume social services as much as Blacks and Hispanics, vote Republican. Blacks and Hispanics, who disproportionately consume social services, naturally vote Democrat more.
Also, as Democrats know they can win more and more elections by just importing more poor people to sit on welfare, that's exactly what their strategy has been. And it's an effective one too - and it is working, and will continue to work.
Trump may win again this year, but from 2024 onward, it will be a clear Democrat sweep, due to the USA importing more people of colour who use higher levels of welfare, and thus vote Democrat.