This quote even made its way into an excellent exposé of Israel's deadly decades-long relationship with apartheid South Africa, Sasha Polakow-Suransky's The Unspoken Alliance: Israel's Secret Relationship with Apartheid South Africa. In fact, I repeated part of the quote in my own review of the book, much to my regret. Later, I discovered that the King letter was a hoax.
We hear much talk about Gentile attitudes towards Jews, but seldom do we hear about Jewish attitudes towards Gentiles. It took more than chutzpah to forge the MLK letter cited in the article, it took good, ol'-fashioned, sectarian contempt. Zionism is racism.
http://socialistworker.org/2012/03/01/using-king-to-sell-apartheid