Arguments for xenophobia?
Divide society. National barriers, religion and cultures all cause an us and them mentality. Technology has brought us closer together meaning we need more inclusive mentalities then divisive ones. If our world was ever attacked the enemy would not need to divide and conquer as we have already done that ourselves.
In the modern world there are still in groups and out groups and people will always look after their own. If shit ever hit the fan in modern society people wouldn’t go out and help strangers they would help their family and friends and their local community which would most likely be the same religious, racial or cultural group.
It is an evolutionary throwback. The instinct of xenophobia comes from our old brain, the one we evolved to have over a million years ago. It is also the same brain that is responsible for anger and anxiety. While these three things were important in hunter gatherer times we have no need for them now. We must use our rational new brain to overcome unnecessary instincts in order to prosper as a civilisation.
Safety first. While acceptance and tolerance are important safety and survival are always the first priority. It times of strife us vs them group mentalities form and if you have shunned your own group and welcomed another you are going to find enemies on all sides.