Just because something is no longer "acceptable" doesn't mean it won't happen. Russia invaded Ukraine multiple times recently and killed a lot of people while most of the rest of the world has done little or nothing to stop it.

Every person alive today is survivors of survivors of survivors⁵ of people who have faced foreign invaders. Being suspicious of foreigners (men only) is part of human DNA, just like being suspicious of spiders and heights. War is our destiny, war has always been with humanity for millions of years. How many war victims would it take before you would admit to "xenophobia" being rational? How many of our ancestors throughout the eons were killed by spider bites for it to be encoded as a fear?