The letter posted by Wolf turns out to be a hoax. It took a long time to realize that it was a hoax because it in fact does accurately reflect Dr. King’s beliefs. He spoke out against the oppression of Jews in the former Soviet Union before American Jewish leaders did. (One can seriously argue that this created a chilul HaShem as a Protestant Christian minister was expressing more interest in the fate of oppressed Jews than were any prominent Jews at the time.) He was outspoken in his support for the State of Israel. He spoke out on these matters at a time when they were not popular causes and there was little to be gained politically by doing so. And he welcomed the support of Jews in the civil rights movement. Far from being an anti-Semite, he was truly a righteous gentile.
The semi-official Bronx celebration of Martin Luther King Day is held in an orthodox synagogue. That is entirely appropriate.