Joseph attacked the character of even close associates who chose to dissent and expose what they felt was inappropriate behavior.

Oliver Cowdery exposed Joseph’s clandestine relationship with Fanny Alger calling it that "dirty, nasty, filthy affair of his and Fanny Alger's."  While Joseph did not deny the relationship, apparently he would not admit to adultery. (Fawn Brodie, No Man Knows My History, p. 459; Richard L. Bushman, Rough Stone Rolling, p. 323).  Cowdery’s persistence in the matter and his participation with other dissenters led to his excommunication from the church.

In a letter dated December 16, 1838, Joseph Smith said that "John Whitmer, David Whitmer, Oliver Cowdery, and Martin Harris are too mean to mention" (History of the Church, vol. 3, p. 232). Smith was very upset with David Whitmer, one of the three witnesses to the Book of Mormon: "God suffered such kind of beings to afflict Job.... This poor man who professes to be much of a prophet, has no other dumb ass to ride but David Whitmer, to forbid his madness when he goes up to curse Israel; and this ass not being of the same kind as Balaam's,... he brays out cursings instead of blessings. Poor ass!" (History of the Church, vol. 3, p. 228). 

David Whitmer would later express his disapproval in writing. He exposed Joseph’s failed prophecy that predicted selling the Book of Mormon copyright in Canada.  He alsorevealed that Joseph had gone back and made changes to earlier published revelations, adding in material that had not been their previously (see Address to all believers in Christ, here).  Click to see examples of Joseph’s modified revelations here

Before driving the dissenters from Far West, Missouri, the Mormons wrote them a very threatening letter. In this letter the dissenters were accused of stealing, lying and counterfeiting:

Whereas the citizens of Caldwell county have borne with the abuse received from you at different times,... until it is no longer to be endured;... out of the county you shall go,... depart, depart, or a more fatal calamity shall befall you.

After Oliver Cowdery had been taken by a State warrant for stealing, and the stolen property found ... in which nefarious transaction John Whitmer had also participated. Oliver Cowdery stole the property, conveyed it to John Whitmer ... Oliver Cowdery, David Whitmer, and Lyman E. Johnson, united with a gang of counterfeiters, thieves, liars, and blacklegs of the deepest dye, to deceive, cheat, and defraud the saints out of their property.... During the full career of Oliver Cowdery and David Whitmer's bogus money business, it got abroad into the world that they were engaged in it.... We have evidence of a very strong character that you are at this very time engaged with a gang of counterfeiters, coiners, and blacklegs,... we will put you from the county of Caldwell: so help us God (Letter quoted in Senate Document 189, February 15, 1841, pp. 6-9B).