Because it is common for people to think that any foreigner influences acts of terrorism.
Explanation:
London believes that immigration restrictions in the United States are based on prejudice and not on rational facts and arguments.
This is because it is common for people to relate terrorist acts to any foreigner they see, and often these acts are shared by the Americans themselves and foreigners want to enter the country just to study or work. These restrictions increase cases of prejudice in the country and prevent Americans from having the valuable experience of living a very rich and valuable cultural diversity.
