Frederick Christ (pronounced Krist) Trump was born in New York City in 1905. From World War II until the 1980's, Mr. Trump would tell friends and acquaintances that he was of Swedish origin, although both his parents were born in Germany.This says nothing of the earlier war. New York City was probably not a bad place to be of German descent in 1917 and 1918, being large and polyglot enough that hardly anyone would stand out. Some places were not so good. The jingoism of WW I is pretty well forgotten now--anyone who can remember the armistice is at least 100--but it was strong while it lasted. Various states restricted instruction in languages other than English; evidently this was with a view to restricting instruction in the German language, both as subject and as language of instruction, for the cases that made it to the Supreme Court did involve German. Some warm patriots took matters into their own hands, burning high school German textbooks. M.F.K. Fisher wrote of a rock breaking a parlor window in her family's home while her mother and an uncle were singing German songs. Texans whose last old-world allegiance was to the Tsar (Volga Germans) had a bad time. Assorted scholars found the roots of evil in the writings of Goethe, Hegel, Nietzche, etc. H.L. Mencken, who was at least not an advocate of the allied cause ("an American not of English sentiments"), deeply disliked the atmosphere.
Before the war, there might have been reason to doubt the attitude of this population. In 1916, agents of the German government managed to set off the Black Tom munitions depot in Jersey City, preventing some thousands of tons of ammunition from reaching the Allies, killing a few citizens, and shattering a great deal of glass in New York and its suburbs. When war was declared, though, the Germans volunteered or turned out for induction with everyone else--including the Slovak who apparently managed the explosion.
The jingoism gave people something to think about while it lasted. It left no lingering animus against Americans of German descent (hardly a surprise, for they--we--are still the largest ethnic group in the country).