The Patton diary entries are usually quoted from Martin Blumenson's books on Patton. He had access to the diaries through the Library of Congress. While there is isn't any basis for the long quote, he does make mention that he could not see a difference between labor leaders, Jews, and communists. The "lower than animals" and "Semitic revenge virus" parts are quoted in the book too.
There was also a line in a letter to his wife Bea, about communism, the destruction and rebuilding of Germany, etc.... where he says something like "you know my feelings on the Jews", so he must've been wilding in private.
