Why did these refugees choose to come to the United States and not to another other country?

On page 12 of Ngai’s Impossible Subjects, the author mentioned that World War 1 created European war refugees that wanted to seek entry in the United States. Roger’s also mentions in Guarding the Golden Door: American Immigration Policy and Immigrants Since 1882 the various refugee acts after World War 2 which had numerical caps to the number of refugee allowed into the United States (pg 190). He later mentions on page 211 that the United States can “pick and choose which of the tens of thousands of refugees it admits annually”.

Why did these refugees choose to come to the United States and not to another other country? What about the United States seemed to attract them here? How did the numerical caps on the refugee acts play a factor in coming to the United States? (THOSE WERE THE QUESTIONS)