This US disens in this case would be second or third generation germans. The US fell undersuspicion thinking that they were unloyal. The other americans didnt like them, there always watching thmem and suspiciouse that they might try something. Well, the group didnt do any thing but, after the Palmer Raids of the 1920s, the Department of Justice rounded up thousands of foreigners who were alleged communists, anarchists, labor reformers, or otherwise menaces to society. Many were forcibly deported. Males older than 14 who were still “natives, citizens, denizens, or subjects” of Germany became enemies. An act of Congress included women aged 14 and older.
Hope I helped. :)