There is no requirement to become citizen. You get all the benefits of citizenship with a green card except the right to vote. The US also recognizes dual nationality.
I didn’t say there was.. I was expressing my opinion about what I think of people who come here and don’t become citizens. Frankly I ant them to leave
I don’t believe the US recognizes dual citizenship; some other countries do if their citizens take an American citizenship oath, but the US doesn’t allow citizens to take foreign oaths and still keep their US citizenship. Some people believe they have both, but often have renounced their US citizenship without their knowledge (if taking another oath afterwards).