Mobbings, tar and featherings, slander, and murders are part of LDS church history. In the United States of America, where freedom of religion and freedom of speech are major tenets, Joseph and his brother Hyrum were assassinated by a mob intent on eradicating the Mormon religion.
The more people speak evil of Joseph, the more they fulfill prophecy. Joseph related a prophecy in his initial visit with Moroni, the ancient American prophet who was the last of his lineage — left holding the gold plates containing the history of his people:
He called me by name, and said unto me that he was a messenger sent from the presence of God to me, and that his name was Moroni; that God had a work for me to do; and that my name should be had for good and evil among all nations, kindreds, and tongues, or that it should be both good and evil spoken of among all people.