“Guthrie's merciful comeuppance came at the hands of a member of his KFVD audience on October 20, 1937, after he had introduced and played Uncle Dave Macon's appalling "Run, Nigger, Run" on the air. He received from one Howell Terence a letter so politely incandescent - and he was so shaken by it - that he read it out over the airwaves the next day: "You were getting along quite well in your program this evening until you announced your "'Nigger Blues." I am Negro, a young Negro in college, and I certainly resented your remark. No person or persons of any intelligence uses that word over the radio today." Guthrie apologized profusely, dramatically ripped the offending song sheet to shreds before the microphine, and swore that he would never use the word again. He later made the point repeatedly apologizing to the African American community for all the racist "frothings" that he had uttered.”
[Klein, p.149-150]

Note: I think Kaufman is saying his source is Woody Guthrie, Poor Girl's Prayer, Songs of Woody Guthrie (manuscript). Haven't read that one yet.

Bound for Glory came out just a few years later in 1940 and that I have read. As outlined in Kaufman, Woody Guthrie doesn't exactly deny all of it. He simply doesn't acknowledge its existence. Here he's not a former, repressed or flaming racist. He never was a racist. And, my interpretation of Kaufman's source notwithstanding, I can't find where he ever cleaned that up.

Put another way, Woody Guthrie steadfastly maintained the pop culture/Maxine Crissman/Mudcat interpretation of events is myth and he is the one to believe. In the man's defense, it does seem there are some very real problems with the biographies, not that it validates Guthrie by a long shot but still, problems.

The author of the Santa Monica Examine 'Er was no political ignoramus nor was it a simple misunderstanding. If these are the whole of your sources none of us are sufficiently informed on the subject to parse truth from myth... at present.