Considering that the Letter was published by the R-G computer with its own unique spelling choices, it would not surprise me that Mr. Kidd may have actually written "epithet" in his actual physical letter and the R-G computer chose the word actually published.

The correct word certainly fits into the sentence quoted.

"In contemporary use, epithet often refers to an abusive, defamatory, or derogatory phrase, such as a racial."

 Unlike some, I proof what I write and often have to make corrections to what the machine produces.