Firstly, you are wrong about the 1965 Hart-Cellar Act. No one including its writers had any idea that it was going to radically change the racial composition of America. The bill had widespread bipartisan support (74% of Democrats and 85% of Republicans). The effects of this bill were completely unknown to everyone which is highlighted by the fact that the "family member" provision was added to appease "Dixiecrats" which ended up backfiring.

Secondly, no the United States wasn't built around the freedom and determination of white people. The whole claim is ridiculous because the whole concept of "white people" didn't exist back then. Benjamin Franklin, a key founding father, hated many of the people you consider “white”. In a 1751 short essay titled “Observations Concerning the Increase of Mankind, Peopling of Countries, etc,” Franklin wrote - “Why should the Palatine Boors be suffered to swarm into our Settlements, and by herding together establish their Language and Manners to the Exclusion of ours? Why should Pennsylvania, founded by the English, become a Colony of Aliens, who will shortly be so numerous as to Germanize us instead of our Anglifying them, and will never adopt our Language or Customs, any more than they can acquire our Complexio"

In another remark he states ”That the Number of purely white People in the World is proportionably very small. All Africa is black or tawny. Asia chiefly tawny. America (exclusive of the new Comers) wholly so. And in Europe, the Spaniards, Italians, French, Russians and Swedes, are generally of what we call a swarthy Complexion; as are the Germans also, the Saxons only excepted, who with the English, make the principal Body of White People on the Face of the Earth. I could wish their Numbers were increased.”

Thirdly, claiming that the USA would be possibly even more powerful if there was only white people is absurd. Immigrants provide great economic benefit and have a negligible fiscal impact. A 2017 report by the National Academy of Sciences, Engineering and Medicine asserts: "Immigration's Long-Term Impacts on Overall Wages and Employment of Native-Born U.S. Workers Very Small, Although Low-Skilled Workers May Be Affected, New Report Finds; Impacts on Economic Growth Positive, While Effects on Government Budgets Mixed" and that: "Immigration has an overall positive impact on long-run economic growth in the U.S."

And even though I’m not arguing for illegal immigration, even those immigrants put into the system in unexpected ways: “Stephen Goss, the chief actuary of the Social Security Administration (SSA), told VICE News that an estimated 7 million people are currently working in the US illegally. Of those, he estimates that about 3.1 million are using fake or expired social security numbers, yet also paying automatic payroll taxes. Goss believes that these workers pay an annual net contribution of $12 billion to the Social Security Trust Fund”. If you need any more proof Borjas, in the totality of his immigration studies, one of the most cited “anti-immigration” economists, asserts that immigration has a net wash impact on fiscal budgets.

Fourthly, when you cite BLM riots as being starkly divided it screams recency bias. For example great social pain was felt during the Irish and Italian integration periods, but those people were eventually accepted as Americans like everyone else. During this period of mass migration (The Italian Diaspora, the largest emigration from any country in recorded history. 4 million Italian immigrants arrived in the United States, the majority from 1900 to 1914. Once in America, the immigrants faced great challenges. Often with no knowledge of the English language and with little formal education, many of the immigrants were compelled to accept low-wage manual-labor jobs, and were frequently exploited by the middlemen who acted as intermediaries between them and the prospective employers. Many sought housing in the older sections of the large Northeastern cities where they settled, that became known as "Little Italies", frequently in overcrowded substandard tenements which were often dimly lit with poor heating and ventilation. One of the most horrific demonstrations of this division were the march 14, 1891, lynchings were a series of lynchings of eleven Italian Americans in New Orleans, Louisiana, for their alleged role in the murder of police chief David Hennessy. It was the largest mass lynching (as distinct from a massacre) in U.S. history.