✔ 最佳答案
1. There are a lot of reasons, but for example:
a. Passive Immigration Policy
Unlike other countries, the U.S. does not actively enforce immigration law. And no one really cares a person's immigration status. It is possible that a person can be an illegal immigrant for years and still in the U.S. and living.
b. Difficulty in immigration
Unlike other countries, immigration to the U.S. is relatively easy.
c. Foreign relationship
2. In theory, yes. (However, as I can tell, the U.S. is the only major destination of people from Hong Kong who still requires a visa.