Its not straightforward to acquire US citizenship. There are many hurdles to be crossed, for example, moving from a Student Visa to a work visa like an H1-B, after which your employer can to apply for your Permanent Residency (which again is a long process depending on the country you are from) and then you have to wait 5 years before you can apply for Citizenship. You may be able to apply for permanent residency based on relatives in the US or apply for asylum, and I'm assuming the author couldn't use any of the latter methods to get a green card.