We were told our healthy instincts and common sense were "racism", "xenophobia" (and all the other scary -isms and -phobias) and were a certain path to persecution and genocide.

The message is reinforced from a young age by Western culture, education, media, politics, etc.

It was done gradually post-WWII. They broke barriers little by little. In 1950s/60s UK, the average white person (regardless of class) was racially conscious enough that conservative politicians like Enoch Powell and even Winston Churchill could sound racial bullhorns and the party would decisively win elections. No one ever wanted coloured immigration, it's just that over time it became normalised and less PC to talk about. People, even in WN circles, talk about how "extreme" the idea of repatriation is.... but that was on the Conservative Party manifesto until as recently as 1983, when Margaret Thatcher was PM.