They also complained that they are becoming less and lesser British. Losing cultural identity to non-British Europeans?
Well, nobody in the EU (or the rest of the world) complained when they are forced to use English. It robs us of our cultural identity, especially our language... pot calling the kettle back.
The stereotypically snobbish French gladly accepted a Corsican Italian descendant as their emperor and proudly emblazoned their history books with his achievements. Heck, the Germans even repeatedly elected furious Austrian leaders to ruin their country.
Wouldn't the British be glad that a vengeful bunch of Poles and Czechs defended their airspace alongside the other nations from marrauding Goering's air force? How about the dependable, rough, and tough bunch of elite Nepalese and northern Indian soldiers?
In Jakarta at least, British embassy is now located in Setiabudi regency. The regency named after Indonesian national hero, which is an Indonesian-born Dutch German named Danudirja Setiabudi (Ernest Douwes Dekker). If we were so xenophobic then, nobody would have taught us the concept of "nationhood", if it werent a bunch of sympathising Dutch and Dutch-educated locals.
Oh in case of USA: Steve Jobs's biological father is Syrian born, Elon Musk is from South Africa, Satya Nadella (Microsoft's CEO) is from India. If nobody migrates to USA, they won't have Boeing (German), Bell (Scotland), Tesla (Serbian), and the lot. Practically wiping off more than 50% of their DJIA companies.
Self-inadequacy leads to xenophobia, really.