Janet Thomas, "What Did Joseph Smith Really Look Like?", New Era, Dec. 2005, 28 To everybody he was known as ‘Young Joe Smith,’ to distinguish him from his father, who was ‘Old Joe Smith.’”(John Henry Evans, Joseph Smith: An American Prophet (1946), 37. (what I could find of this book online begins at page 40ish...)) October 1979 Sessions, The Contributions of the Prophet Joseph Smith, N. Eldon Tanner New York Sun of 4 September 1843 stated: “‘This Joe Smith must be set down as an extraordinary character, a prophet-hero, as Carlyle might call him. He is one of the great men of this age, and in future history will rank with those who, in one way or another, have stamped their impress strongly on society’” (History of the Church, 6:3). April 1984 Sessions, The Magnificent Vision Near Palmyra, James E. Faust The New York Sun in the late summer of 1843 said: “That Joe Smith, the founder of the Mormons, is a man of great talent, a deep thinker, an eloquent speaker, an able writer, and a man of great mental power, no one can doubt who has watched his career. That his followers are deceived, we all believe … “Few in this age have done such deeds, and performed such apparent miracles. It is no small thing, in the blaze of this nineteenth century, to give to men a new revelation, found a new religion, establish new forms of worship, to build a city, with new laws, institutions, and orders of architecture,—to establish ecclesiastic, civil and military jurisdiction, found colleges, send out missionaries, and make proselytes in two hemispheres: yet all this has been done by Joe Smith, and that against every sort of opposition, ridicule and persecution.” (History of the Church, 6:3.) Although I'm not sure those count as primary sources. I know I've read dozens of time non-hostile references to him as "Joe", but looking now with google, I'm not able to locate any. For the most part those who believed he was a prophet of God gave and give him the respect of using his full name and most of the 'history' we have has been passed through the church which followed suit, "correcting" it to Joseph where needed. "Joe Smith" was often used by those hostile to him or the church, and those instances abound, however "Joe" is a perfectly acceptable substitute for "Joseph" and was used often enough in informal conversation. Probably because of the church's early persecution complex, derogatory use of "Joe" was left intact, where as familial use of Joe was corrected, because we respect him by using his full name. I suspect the places I've read "Joe Smith" are on the bookshelf in the other room, and that most online search results are either hostile or neutral because those are the ones used most often. Regardless, "Joe" is not innately a derogatory form of "Joseph" and I will not seek out offense over something so idle as someone who doesn't believe him to have been a prophet of God not giving him the respect I do. Had his name been Richard Smith, I might feel differently.