Ethnic Germans by and large were not as discriminated against as the aforementioned groups in the late 19th and early 20th centuries and assimilated a bit easier due to the fact they were usually Protestant(though some Catholics suffered persecution) and seen by some as a bit better racially. It was rare to see "No Germans need apply" vs Irish and Italians etc. They also tended to be more skilled labor vs unskilled labor and fanned out from major cities into the countryside more. The combination of less ethnic +religious discrimination+ usually more educated immigrants + more of a tendency to move out of larger cities where organized crime flourishes more easily discouraged the formation of exclusively German criminal organizations (though there were German affiliates of such organizations of course). That is not to say they did not form other associations of borderline legality e.g. The German-American Bund which was exclusively German-American and involved in some crime as well as inciting political violence and supporting Nazism.