The cognitive dissonance of believing that recent immigrants forcibly conscripted went to war to end slavery remains. It’s a peculiar belief no matter what sort of deflection or smokescreen you throw up.
The popular myth that the Union army was made up largely of immigrants conscripted right off the boat is the result of people accepting Gangs of New York as a work of history. The fact of the matter is that the vast majority of foreign-born immigrant soldiers had been in the U.S. before the rebellion broke out, and the fought for the same reason that native born Americans fought. Because they believed that this was their country too.