I wouldn't know, regardless, I wouldn't take anything as absolute truth from skeptic.com. The source used for the quote is "(cited by Wilhelm Niemoller in Kampi und Zeugnis der bekennenden Kirche — Struggle and Testimony of the Confessing Church, p. 526. and Cochrane)"
From reading the article, I see that the quote has been used in Time magazine.
Time Magazine, December 23, 1940 (page 38).
1 “The best tribute to the spirit of Germany’s Christians comes from a Jew and an agnostic (
Time, Sept. 23) — the world’s most famous scientist, Albert Einstein,”
LM, do you have access to this? "Unpublished letter, Einstein Archives, item number 58-548."