The Germans were immigrants who came in waves from the early 1800's forward. Germans made up the largest minority percentage of the United States Army in the Civil War. That's not surprising: they are the largest identifiable group of immigrants in the country today, and they were then as well.
They are my kin. My Father's family came here in 1807. Two generations of my grand sires fought for America during the Civil War. They were, in fact, Americans, not Germans.
Yeah, there were draft riots -- so what? This has nothing to do with your idiotic claim that Irish and Blacks were used for "canon fodder." The only general who used Blacks for "cannon fodder" was Bobby Lee, who put Black Union prisoners under fire to construct his defenses, in clear violation to the laws of War.
The percentage of foreign-born soldiers in the Union Army was actually smaller than their percentage of the population.
My father was 1/2 German, and his kin were among those who fought in the Kansas Union regiments.
On my mom’s side I have ancestors who fought for the CSA and others who fought for the USA. Family legend has it that one non-direct ancestor was a “galvanized Yankee” who fought for the South till captured, then agreed to fight for the Union against the Indians. :)