> America put men on the moon without millions of foreign immigrants
Did you drop out of middle school?
America saw the highest rate of immigration in history between ~1910-1960. A majority of the scientists and engineers in the Apollo program were immigrants or children of immigrants.
> Why is it only ever white nations that are expected to let everyone else in?
They are not, have you considered moving to Russia?
Do you know of the fable of a goose that laid a golden egg once a day?
You are proposing to kill the goose to see if you can get multiple golden eggs at once.
> country with an identity
Like it or not, the identity is 'land of opportunities' and not 'land of anglo-saxons who emigrated before ~1850'