I don't think they think white people built America. I think they believe (and I'm creating this out of whole cloth, just theorizing) central banks and WW2 created the wealthy America the boomers got to enjoy. They probably think, with their banking power it doesn't matter what race is involved, because look at how comfortable the wealthy are in third world countries, the true elite have always been comfortable and capable of fleeing to wherever they want. They will keep sucking America dry as much as they can for as long as they can, establish themselves in their little elite enclaves, and maybe move to countries they plan on enriching, like India, and live like kings there where there are no pesky rights anyone pretends exist.
The America of the middle class bloom had been allowed to come to exist only because of major pro-labor pushback starting in the 1930, after the Great Depression in America and other events outside of it. From USSR to National Socialists in Germany, left and pro-labor movements had become very popular and became a real threat to corporate/banking elites, which had caused them to give major concessions and share wealth. Things like SSA pensions were created and corporate profits had been shared with the public, creating strong middle class and social programs.
None of it happened out of anyone's "benevolence", good will or "sense of brotherhood", it was pure fear of revolutions or stuff like electing national socialists. These victories of the common man had began to vane around 1970s and the movement had been in the opposite direction ever since, the corporate-banking elites has been pulling the blanket back, this is when real wages began to decline and when income inequality started to increase again instead of decreasing (it had been decreasing since late 1930s earlier).
Elites will be very comfortable in third world countries for sure (until the revolutions sweep them away but they hope that technocracy can prevent this). Once you understand that in America - and not just in America but anywhere in that general system - a human is merely a resource for extracting profit, everything becomes very clear and kind of predictable.
That Normal Rockwell world is long gone now.
To elaborate further, the stage of European settlers needed to populate, clear, develop the land in North America is long over, there was massive profiting off resource exploration at that time, land, furs, gold, forests, then oil, gas, coal, other resources being discovered and extracted, giving massive profit margins (research, even most fur traders of the old days were corporate slaves,by the way, they did not own their outfits and were in debt to the fur trading companies).
This resource market is now fully saturated, no new exciting stuff coming, no superprofits. May be a lithium mine here and there, that's it. Profits stagnate. New resource to exploit is AI, internet and computers earlier since the 90s. Now tell me why stable, thoroughly middle class Euro population out of old Norman Rockwell painting picture is needed here? It is not. Just like they put masks on while USD was devalued twice, they will do what the are told to do from then on. No one owes anyone loyalty, or anything else, in this kind of world where only profit matters. My last paragraph describes what goes through Trump's and Miller's minds daily, by the way
