等了好多天,小米终于回信了: In answer to your question "Are you legally authorized to enroll at an academic institution in the United States?", the answer is no. You will be contacted after you have applied to the program with details on the visa application procedure. 我之前在邮件中说明自己是国际学生,不在美国生活,现在也没有持有签证。
以前也有同学发帖问这个问题,根据小米的回答,我认为这个问题的含义是,如果你不是美国公民或者永久居民或者持有签证,就需要办理签证等手续后,才legally authorized to enroll,而不是说你有没有“合法去美国学校学习的资格”。