The Real Truth

[Hess1865]

That Nazi would be Ernst 'Putzi' Hanfstaengl (1887-1975)
Putzi was born in Germany, his dad was German while his mother was American. Interestingly enough his mother was related to Union Civil War General John Sedgwick.

Hanfstaengl graduated from Harvard in 1909.
Going back to Germany, he fell in with Hitler and his crowd in the early days of Nazism. After a few years there was friction between him and Josef Goebbals, Hitler's propaganda minister.
Seeing the writing on the wall, Hanfstaengl defected to England, where he was held as a prisoner. Later in the war he came to the US and worked for FDR.

So that's probably how he came to get his name on the wall at Harvard