In a world of war, it is natural for the citizens of a country or the members of a distinct ethnic group to be suspicious of foreigners.
Any assistance given to foreigners, even some that involves mutual benefit, can be dangerous.
Thus, regulations that make it difficult for foreigners to visit, restrictions on where they can go, restrictions on employment, and discriminatory travel, employment, or business laws are to be expected and often desirable for practically everyone. In a world of war and a world of peace, it is natural for anyone to oppose competition from workers and businesses who can offer a lower price or more desirable service. Many citizens and members of a distinct ethic group prefer restrictions and discriminatory treatment against foreigners in order to improve their employment or business prospects. However, whatever improvement they achieve in this way comes at the greater expense of buyers, who must pay higher prices than the competition would allow. Although such restrictions are good for some, they are bad for most.