The immigration you mentioned was important and helpful, because it helped to build the nation in its formative period. Most of it was from European countries, so there were plenty of cultural differences, but racially it was predominantly white European. So people would quickly assimilate to a common purpose.
From an American Indian’s perspective this immigration was pretty bad. In the main they resented It, as you would if you were getting kicked off your land, killed, or told what to do by invaders. Funny how immigration is always touted as good.
Once upon a time I might have agreed with that statement, it all sounds good on paper, equality and fairness, human rights for all, kumbaya . Racism is a Marxist term used to gaslight, people(usually white people) into doing something against their own interest. It has been overused so much just like Nazi, or bigot, to have become powerless to anyone with 2 braincells.
After seeing what happens in countries like Zimbabwe, South Africa, in practice it just doesn’t occur that way.
Zim became very hostile quickly, to white people and most of them fled. Those that stayed risked losing their productive farmland, or being murdered if they refused to leave. The end result the country turned from being the richest, most productive country in Africa, to one of the worst economic basket cases the modern world has seen.
South Africa was perceived as an evil apartheid culture, think Lethal Weapon 2. International pressure in the form of economic sanctions was successful, in forcing the white government to share power with the native population. It all started off well, truth in reconciliation tribunals, where the natives grievances could be recognised as fact, yet no retaliation was threatened as people were now all supposed to get along. It was promising in the first few years, now you have white farmers getting murdered for their land, and talk of politicians legitimising this by legislating compulsory government acquisition of land. After 30 odd years of power sharing, and now predominantly black rule the country is in worse state than ever, both economically , and socially. This is worse for the majority of black people too, due to tribal factions that only pay lip service to fairness and equality. So please forgive me If I think objectively that countries don’t do as well, when the majority of people become the minority.