Partly one has to recoginze that there was a severe event that de-germanized the population WWI. My great grandfather had never gotten his second citizenship papers, so when the newspaper published a list of aliens his name appeared and his door got painted yellow (he came to the us at age 1 or 2 and was in his 50s in 1917). Perhaps a better example on a gravestone in Darmstadt Indiana, the husband who died in 1914 has a german inscription the wife who died in 1921 has an english inscription. Its only in the 1980s that german heritage came back to be allowed. The whole event was IMHO a very traumatic one for those of german heritage. This may also be a factor, since a a large number of folks came over to avoid religious differences or the draft (german not us). I might put it that the german group was less puritian than other groups (in the sense of I know whats better for you than you do for example prohibition.)