As my shrink wife might say, your comment is "projecting." Our laws *were* being used as a demographic weapon, you said so yourself above, to keep northern Euros in, others out. When JFK came campaigning in my Italian neighborhood in Brooklyn in 1960, he said that Nixon had supported the discriminatory immigration law then in force which was biased against Italians and others. That law was changed in 1965, removing those biases. (Our refugee laws actually remained biased in favor of those fleeing communist countries/Middle East until that geographic/political bias was ended with the Refugee Act of 1980.) Hence the new, more diverse population of Immigrants since 1965. (When has our nation NOT been flooded with foreigners?) Thence the repeat of the periodic US freak-out over immigrants that Trump sensed and exploited.
That the country having a white minority in its future has been (probably accurately) predicted long before Clinton. Time magazine did a cover story on America's changing face around 1970, puttIng a, well, face on its cover of a brown-skinned woman of indeterminate ethnicity. North America became whiter after 1492, then darker after 1619, then whiter with the arrival of the scorned Irish, then browner with a tinge of yellow when Italians, Jews, Japanese and Chinese showed up.
A sad side to our wonderfully diverse country is that folks like Tucker Carlson keep putting down what makes us more special than many other nations. To use a baseball analogy, which was more interesting to watch in the 1950s (I am dating myself, but trust me), the diverse, daffy, winning Brooklyn Dodgers or the boring, matchine-like winning NY Yankees? And folks like Tucker have been spinning BS analyses for over a century. My fave was some theory that Sicilians, Irish and Jews were barely white since they came from the southern, northwestern, and eastern extremes of white Europe.