有的媒体选择不报原因，要看原因看这个link

https://www.abc15.com/news/region-southeast-valley/tempe/arizona-state-university-students-denied-entry-to-us-over-alleged-academic-fraud

Sources close to the situation tell ABC15 that the students were in violation of their F1 student visas related to academic fraud. The sources said investigators apparently discovered evidence that the students were paying to have their school work completed for them, which is a violation of the F1 visa requirements and regulations.